GMPV9.2

The 2021 eruption of Cumbre Vieja volcano (Canary Islands)

This session is devoted to the most recent eruption of the Cumbre Vieja volcano, which started on Sept. 19, 2021, on the island of La Palma after 50 years of repose. Volcanic unrest was recorded in Oct. 2017, when a seismic swarm was located at more than 20 km depths. Nine additional swarms followed, the last one was recorded in June 2021. Geochemical anomalies followed this increased seismicity indicating a magmatic recharge at depth. On Sept. 11, 2021, a new seismic swarm was observed at shallower depths (10-12 km), indicating a possible magmatic intrusion. This was confirmed when geodetic monitoring networks on the island started showing clear signs of inflation. The seismicity increased in frequency and intensity with many felt earthquakes. Seismic activity accelerated in the morning of Sept. 19 when a strong shallow earthquake was widely felt on the western part of the island. This was the precursor of the eruption, which started at about 14:10 UTC on the same day. A series of vents opened along a fissure close to Los Llanos on the western flank of Cumbre Vieja volcano. The eruption displayed vigorous lava fountaining and powerful Strombolian explosions while lava effusion produced a compound Aa flow field. The eruption has destroyed hundreds of buildings, plantations as well as cutting vital transport routes.
This session is open to contributions aimed at geological, geophysical, geochemical and volcanological studies of the eruption and its precursors and, more in general, to studies that can help better understanding the eruptive dynamics. We also welcome contributions focused on the management of scientific communication during this crisis and the management of the volcanic emergency.

Co-organized by GI5/NH2
Convener: Luca D'Auria | Co-conveners: Carmen López Moreno, Carmen Solana
Presentations
| Mon, 23 May, 08:30–11:48 (CEST), 13:20–14:50 (CEST), 15:10–16:10 (CEST)
 
Room D2

Session assets

Session summary

Presentations: Mon, 23 May | Room D2

Chairpersons: Luca D'Auria, Carmen López Moreno
08:30–08:34
08:34–08:44
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EGU22-11549
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solicited
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Highlight
Carmen Lopez, Maria Jose Blanco, and Ign Team

The monitoring of the anomalous signals associated with the ongoing magmatic process occurring in La Palma, and their interpretation, allowed the proper forecast and management of the last eruption in the Canaries. This eruption occurred 10 years after the submarine eruption in El Hierro island (Tagoro, 2011) and 50 years since the last eruption in La Palma island (Teneguía, 1971). The early signs started in October 2017 and lasted until 2021, with the occurrence of 7 short lasting seismic swarms located at depths between 20-30 km, below Cumbre Vieja volcanic edifice (the volcanic active zone of the island during the last 125 ky). Also, during this period, several geochemical signals were registered associated with the emplacement of magma below the island and the local changes of stress. The eruption was preceded by 1 week (September, from the 11th to the 19th) of strong unrest, with seismic activity (shallower than the previous swarms) and surface deformations. Data registered by the IGN volcano-monitoring network, were transmitted, processed and interpreted in real time, and have been essential to the management of the volcanic crisis, providing the Canarian Civil Protection with valuable scientific information to undertake the preventive actions in each phase of the crisis in order to mitigate its effects. Data and samples collected (lava, ashes, water, gases) will allow to identify the causes and mechanisms of this eruption and will shed light on the origin of the magmatism in the Canaries.

How to cite: Lopez, C., Blanco, M. J., and Team, I.: Instituto Geográfico Nacional Volcano Monitoring of the 2021 La Palma eruption (Canary Islands, Spain), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11549, https://doi.org/10.5194/egusphere-egu22-11549, 2022.

08:44–08:54
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EGU22-12491
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solicited
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Highlight
Nemesio M. Pérez, Pedro A. Hernández, Gladys V. Melián, Eleazar Padrón, María Asensio-Ramos, José Barrancos, Germán D. Padilla, Fátima Rodríguez, Luca D'Auria, Cecilia Amonte, Mar Alonso, Alba Martín-Lorenzo, David Calvo, Claudia Rodríguez, William Hernández, Beverley Coldwell, and Matthew J. Pankhurst and the International Collaborative Research TEAM

Cumbre Vieja (220 km2) is the most active volcano in the Canary Islands. It has been the location of 8 of the 17 historical eruptions in the archipelago during the last 600 years. The establishment of a geochemical monitoring program by our research group for the volcanic surveillance of Cumbre Vieja started in 1997. This program was mainly focused on diffuse degassing monitoring because of the absence of visible volcanic degassing manifestations (fumaroles, plumes, etc.) as well as other obvious geothermal features at Cumbre Vieja up to the 2021 eruption which started on September 19, ended on December 13 and lasted 85 days.

The INVOLCAN’s soil degassing monitoring at Cumbre Vieja is carried out by means of a geochemical instrumental permanent network (soil CO2 efflux, soil gas 222Rn and soil C isotope ratio) and regular geochemical surveys covering the entire area of Cumbre Vieja (diffuse CO2, He and H2 emissions). Several soil degassing anomalies have been observed and some of them years before the 2021 eruption, which illustrates the importance of diffuse degassing monitoring for volcanic surveillance. The single visible manifestation of volcanic degassing at La Palma is a cold CO2-rich site at Taburiente volcano. Regular helium-3 emission monitoring of this observation site has been carried out since 1991 in collaboration with Tokyo Univ., and provided a clear early warning signal of the 2021 Cumbre Vieja eruption. Because of the registration of seismic swarms, and to strengthen the INVOLCAN geochemical monitoring program of Cumbre Vieja volcano,  regular sampling of groundwater for chemical and isotopic analysis started in October 2017. The results of this hydrogeochemical monitoring also showed significant changes related to the recent volcanic unrest of Cumbre Vieja.

Since the 2021 eruption onset, INVOLCAN performed daily observations of SO2 emissions using a miniDOAS in traverse mode, on terrestrial (car), sea (ship) and air (helicopter) mobile position recording relatively high SO2 emissions (> 50.000 t/d). Static scanners and satellite instruments were used also to monitoring the SO2 emission released by this eruption; a task lead by the volcano research group of Manchester University. Additional plume geochemical monitoring was carried out using OP-FTIR spectrometers and UAV, helicopter and ground-base MultiGas units to characterize the chemical composition of the plume degassing in collaboration with scientists from Manchester Univ., Palermo Univ., UCL, INGV, IPGP and Azores Univ.  Carbon isotope analysis of the CO2 gas plume was also undertaken in collaboration with New Mexico Univ. Analysis of pristine ash leachates has been also performed in collaboration with Durham Univ. and Tokyo Institute of Technology since it is often used to estimate the composition of the gas phase during volcanic eruptions and provides important information on the eruption processes was also performed.

The results of these geochemical observations during the inter-eruptive, pre-eruptive, eruptive and post-erupive phases have been tremendously useful to understand the recent magmatic reactivation of Cumbre Vieja volcano.

 

How to cite: Pérez, N. M., Hernández, P. A., Melián, G. V., Padrón, E., Asensio-Ramos, M., Barrancos, J., Padilla, G. D., Rodríguez, F., D'Auria, L., Amonte, C., Alonso, M., Martín-Lorenzo, A., Calvo, D., Rodríguez, C., Hernández, W., Coldwell, B., and Pankhurst, M. J. and the International Collaborative Research TEAM: The 2021 Cumbre Vieja eruption: an overview of the geochemical monitoring program, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12491, https://doi.org/10.5194/egusphere-egu22-12491, 2022.

Seismology and Acoustics
08:54–09:00
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EGU22-9449
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Virtual presentation
Carmen del Fresno, Simone Cesca, Itahiza Domínguez Cerdeña, Eduardo Díaz-Suarez, Claus Milkereit, Carla Valenzuela, Rubén López-Díaz, Torsten Dahm, and Carmen López

A moderate seismicity accompanied the dike intrusion which preceded the 2021 volcanic eruption at La Palma, Canary Islands, Spain. Nevertheless, the largest magnitudes were recorded during the eruption, from September 19th to December 13th, 2021. This volcanotectonic activity accompanied the upward magma transfer to feed the eruption and provides important clues to the understand the feeding system geometry, as we are dealing with the first fully monitored eruption in the island. Seismicity during the eruption displayed a stable bimodal spatial distribution, with hypocenters clustering at two, well separated depth intervals. A shallower seismic cluster was active beneath the central area of Cumbre Vieja  ~10-14 km depth, starting by September 27, just after a short quiescence of about 3 hours in the tremor signal and with peaks of intensification rates in mid and late November. A deeper and larger cluster (~33-39 km) extended further to the Northeast. Here, the activity started with some delay on October 5th and the cluster was mostly active over October and November 2021, reaching a peak magnitude mbLg 5.1 November 19th, 2021, the largest earthquake of the whole seismic sequence. In this study, we use a variety of seismological methods to resolve hypocentral and centroid location at the two clusters, as well as full moment tensors for 156 earthquakes, including largest ones at each cluster. The hypocentral relocation of 7150 earthquakes reconstructs the geometry of the active seismogenic structures, resolving small-scale details within each of the two clusters. The centroid moment tensor inversion resolves different families of moment tensors in each cluster including earthquakes with almost reversed focal mechanism that respond to local stress perturbations introduced by the magma rise through a complex path and multiple magmatic reservoirs. The source studies are complemented by a temporal analysis of the families based on waveform characterization, which allows to reconstruct the timeline of the magma transfer and seismogenic processes. Our seismological analysis provides details of seismicity accompanying the volcanic unrest at La Palma and documents the evolution of seismogenic processes in response to the rise of magma batches through the complex plumbing system.

 

How to cite: del Fresno, C., Cesca, S., Domínguez Cerdeña, I., Díaz-Suarez, E., Milkereit, C., Valenzuela, C., López-Díaz, R., Dahm, T., and López, C.: Complex seismicity patterns accompanying the 2021 volcanic eruption at La Palma, Canary Islands, Spain, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9449, https://doi.org/10.5194/egusphere-egu22-9449, 2022.

09:00–09:06
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EGU22-10309
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Highlight
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Virtual presentation
Itahiza Francisco Domínguez Cerdeña, Laura García Cañada, Anselmo Fernández García, Carmen del Fresno, and Eduardo Andrés Díaz Suárez

On 19 September 2021 at 14:10h (UTC) a volcanic eruption started in the South of La Palma (Canary Islands). Just a week earlier, on 11 September, an intense seismic swarm had begun in the area, with the hypocenters located at 11 km depth in the first days but gradually approaching the surface throughout the week. This activity, together with an evident deformation recorded both at the island's GNSS stations and in InSAR measurements, were key to the monitoring of the reactivation and estimate the eruption onset parameters. 

In this presentation we show the results obtained using the volcanic monitoring network of the Instituto Geográfico Nacional (IGN) before La Palma eruption. Consistent results have been obtained combining seismic and geodetic techniques. We have used hypoDD relative location algorithm to improve the hypocenters of 1323 earthquakes of the IGN catalog. Deformation results have been obtained using Sentinel-1 images to get the InSAR interferograms and GNSS time series have been computed using double differences with Bernese software considering a regional network.  

At the beginning, seismicity was 11 kilometers below the central part of Cumbre Vieja and for ~6 days it migrated towards the surface in northwest direction. Meanwhile, the deformation indicated a magma intrusion in the area of the activity, showing a good correlation with seismic data. Some hours before the eruption started there was a sudden change in the migration direction pointing north while hypocenters considerably accelerated its trend to the surface. This episode was accompanied by a rapid deformation of more than 7 cm to the South and 5 cm upwards in the closest GNSS station. Finally, 4 hours before the eruption, an increase in the shallow seismicity rates was observed. Most of the earthquakes were not felt by the island population and moderate magnitudes were recorded reaching a maximum of 3.8 (mbLg). InSAR results during the whole process show more than 20 cm of deformation in LOS (Line of Sight) to the South of the eruption vent. 

Hours before the eruption, the seismicity behavior and the deformation shape indicate the existence of an intruding dike that culminated in eruption and that would be the last stage of a magmatic process that had begun at least four years earlier with the seismic reactivations on the island. 

How to cite: Domínguez Cerdeña, I. F., García Cañada, L., Fernández García, A., del Fresno, C., and Díaz Suárez, E. A.:  Dike intrusion before the 2021 La Palma eruption , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10309, https://doi.org/10.5194/egusphere-egu22-10309, 2022.

09:06–09:12
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EGU22-4591
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Highlight
Luca D'Auria, Ivan Koulakov, Janire Prudencio, Iván Cabrera-Pérez, Jesús M. Ibáñez, Jose Barrancos, Rubén García-Hernández, David Martínez van Dorth, Germán D. Padilla, Monika Przeor, Victor Ortega, Pedro Hernández, and Nemesio M. Peréz

The 2021 Cumbre Vieja surprised the worldwide volcanological community for its peculiar, unexpected features. Among these are the quite explosive character, even having the erupted magma a femic composition, the long duration (almost three months) and the huge erupted volume (more than 200 Mm3). The eruption was preceded by seismicity starting in Oct. 2017. However, the genuine precursory seismicity began only eight days before the eruption, with an evident upward migration of hypocenters. During the eruption, the seismicity mainly was concentrated at a subcrustal (10-15 km) and an upper mantle (20-25) depth.

Before and during the eruption, we collected a dataset of 11,349 earthquakes recorded from 7 October 2017 to 13 to December 2021 with 140,078 P wave and 155,231 S wave picks. We performed a high-resolution traveltime tomography, obtaining a three-dimensional P and S-wave velocity model up to a depth of about 25 km. The tomographic models evidence the presence of various interesting structures. At shallow depth (< 3 km), we identified a localized low-velocity anomaly interpreted as a volume of hydrothermal alteration. The Moho shows a complex geometry, with an upwelling beneath Cumbre Vieja volcano up to 10 km depth. Finally,  a large deep volume (> 400 km3) is characterized by high Vp/Vs values. This volume can be possibly related to the main magmatic reservoir feeding the eruption.

The tridimensional velocity model also allowed for a precise relocation of the seismicity, providing an interesting insight into the evolution of the eruption. Before eruption onset, magma ascended from about 10 km depth to the surface in a few days. The melt migration occurred along the contact between consolidated oceanic crust and altered hydrothermal material at shallow depth. We postulate that similar structural discontinuities could potentially drive the formation of new eruptive centres during future eruptions.

How to cite: D'Auria, L., Koulakov, I., Prudencio, J., Cabrera-Pérez, I., Ibáñez, J. M., Barrancos, J., García-Hernández, R., Martínez van Dorth, D., Padilla, G. D., Przeor, M., Ortega, V., Hernández, P., and Peréz, N. M.: Tomographic imaging of the magmatic system feeding the 2021 Cumbre Vieja eruption (La Palma, Canary Islands)., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4591, https://doi.org/10.5194/egusphere-egu22-4591, 2022.

09:12–09:18
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EGU22-5133
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ECS
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Virtual presentation
Iván Cabrera Pérez, Luca D'Auria, Jean Soubestre, Monika Przeor, Ivan Koulakov, David Martínez van Dorth, Jesús M. Ibáñez, Víctor Ortega, José Barrancos, Germán D. Padilla, Rubén García-Hernández, and Nemesio Pérez

On September 19th, 2021, a volcanic eruption began on La Palma, resulting in a significant social, economic and scientific impact. Earthquakes were first recorded in 2017, however, the pre-eruptive unrest started on Sept. 11st, 2021, only a few days before the eruption. It was characterized by a seismic sequence with hypocenters located at a depth of less than 10 km and ground deformation that reached more than 20 cm in the vertical component of the GPS. Surprisingly, this episode was very short, however, given the large amount of scientific instrumentation (seismometers, GPS, etc.) operated by the Instituto Volcanológico de Canarias (INVOLCAN) and other scientific institutions, the entire pre-eruptive episode has been accurately monitored, and the civil protection authorities were notified about the development of the volcanic unrest in advance. One of the techniques that have shown great potential in volcanic monitoring is ambient noise interferometry. This method consists in estimating the relative velocity variations using empirical Green’s functions retrieved through the cross-correlations of ambient noise signals. In this study, we applied this technique to the data recorded by six broadband seismic stations that allowed us to estimate spatio-temporal relative velocity variation during the week preceding the eruption.

The overall pattern of the pre-eruptive seismicity shows a progressive westward and upward migration of the hypocenters. However, five days before the eruption, we observed the occurrence of shallow (< 5 km) low magnitude earthquakes, whose hypocenters were detached from the main seismic cluster. At the same time, seismic interferometry detected a decrease in the seismic velocity in the region where such hypocenters were located. Therefore, we interpret those earthquakes as the effect of triggering caused by hydrothermal fluids released by the ascending magma and reaching shallow depths faster than magma.

Furthermore, a couple of days before the eruption, an even more significant reduction in relative velocity variation was observed, possibly corresponding to the rapid magmatic upward intrusion process, which led to the volcanic eruption.

How to cite: Cabrera Pérez, I., D'Auria, L., Soubestre, J., Przeor, M., Koulakov, I., Martínez van Dorth, D., Ibáñez, J. M., Ortega, V., Barrancos, J., Padilla, G. D., García-Hernández, R., and Pérez, N.: Spatio-temporal velocity variations observed during the pre-eruptive episode of La Palma eruption inferred from ambient noise interferometry, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5133, https://doi.org/10.5194/egusphere-egu22-5133, 2022.

09:18–09:24
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EGU22-8183
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ECS
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On-site presentation
Víctor Ortega and Luca D'Auria

The receiver function analysis (RF) is a commonly used and well-established method to investigate subsurface crustal and upper mantle structures, removing the source, ray-path and instrument signature. RF gives the unique of sharp seismic discontinuities and information about P-wave (P) and shear-wave (S) velocity below a seismic station.

This work aims to study the crust and the upper mantle of La Palma up to 40 km depth by using RF analysis. Because of the geological context as an active island, it is expected that Mohorovičić’s discontinuity has a complex geometry under Cumbre Vieja and possibly a high anisotropy can be present. This makes the application of conventional RF function analysis difficult.

That is why in this study, we applied the frequency-domain RF inversion using multi-taper deconvolution. After that, we have applied the transdimensional approach of Bodin et al. (2012) to determine 1D profiles of P and S wave velocities in terms of probability distributions, as well as the probability of a discontinuity to be located at a given depth. This approach does not require establishing “a priori” the number of layers to be used for the inversion.

Our preliminary results allowed us to correlate the different discontinuities besides the stations we got deployed around Cumbre Vieja. We have seen at least for different layers with a significant change in their Vp/Vs ratios. Moreover, we have determined the Moho topography under Cumbre Vieja and the whole island.

These results are compared with the seismicity observed during the 2021 Cumbre Vieja eruption, mainly located at the base of the crust (10-15 km) and in the upper mantle (20-30 km), possibly indicating the presence of two magmatic reservoirs at these depths.

 

References

Bodin, T., Sambridge, M., Tkalčić, H., Arroucau, P., Gallagher, K., & Rawlinson, N. (2012). Transdimensional inversion of receiver functions and surface wave dispersion. Journal of Geophysical Research: Solid Earth, 117(B2).

How to cite: Ortega, V. and D'Auria, L.: Imaging the crust and the upper mantle of Cumbre Vieja volcano (La Palma, CanaryIslands) through receiver function analysis., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8183, https://doi.org/10.5194/egusphere-egu22-8183, 2022.

09:24–09:30
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EGU22-9295
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ECS
Valeria Cigala, Ulrich Kueppers, Caron E. J. Vossen, José Barrancos, Laura Spina, David Fee, Corrado Cimarelli, Julia Gestrich, Markus Schmid, Pedro Hernández, Matthew Pankhurst, Luca D'Auria, Nemesio Pérez, and Donald B. Dingwell

After 50 years of volcanic quiescence, on 19 September 2021, an eruption started on the western flank of the Cumbre Vieja ridge of La Palma, Canary Islands, Spain. The eruption was characterised by simultaneous effusive and explosive activity from a several hundred-meter-long fissure, which later built up a cone and showed variable eruptive behaviour at different vents, suggesting a spatially complex plumbing system. Explosive eruptive activity ranged from mild ash emissions, Strombolian explosions to fire fountaining episodes.

We carried out field measurements to study the variable explosive eruptive activity and associated acoustic signals. A single microphone initially deployed at about 2 km SW of the vents from 6 to 11 October was later replaced by an array of 3 microphones from 6 November to 13 December at about 300 m W of the microphone location in October. The microphones (PCB ½” free field acoustic sensors, 3.15-20 kHz frequency range) were each connected to an OptiMeas SmartPro digitiser continuously sampling at 5000 Hz. The digitisers are GPS synchronised for accurate acoustic array processing. The acoustic array was complemented by a thunderstorm detector continuously recording (since 11 October) lightning and electrical activity generated by the volcanic explosions (Vossen et al., 2022). Additionally, at the beginning of November 2021, thermal videos of the eruptive activity were acquired.

Preliminary analysis of the large and unique acoustic dataset shows varying waveforms indicating evolving source conditions: eruption intensity, source mechanism, vent geometry, fragmentation depth and amount of ash ejected. Moreover, we observe a variability of frequency (peak and mean) and amplitude with time. Further analysis includes the characterisation of the acoustic source location within the growing volcanic edifice and the comparison and correlation with lightning and thermal infrared data to detail changes in explosive activity related to the evolving eruption sources. 


Caron E.J. Vossen et al. (2022), Electrical activity of the 2021 Cumbre Vieja eruption, EGU22-8052.

How to cite: Cigala, V., Kueppers, U., Vossen, C. E. J., Barrancos, J., Spina, L., Fee, D., Cimarelli, C., Gestrich, J., Schmid, M., Hernández, P., Pankhurst, M., D'Auria, L., Pérez, N., and Dingwell, D. B.: Acoustic signals from the 2021 Cumbre Vieja eruption, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9295, https://doi.org/10.5194/egusphere-egu22-9295, 2022.

09:30–09:36
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EGU22-11086
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On-site presentation
Maria Jose Jurado, Carmen Lopez, Maria Jose Blanco, Ruben Lopez, Stavros Meletlidis, and David Moure

We present first results on the continuous monitoring of the 2021 La Palma volcanic eruption (Canary Islands, Spain), from September 2021 to December 2021. During the eruption we installed a 8 level 3-component geophone string and 15 m spacing between geophones in Las Manchas within the restricted area and less than 2 km away of the volcanic edifice. The string was installed on the ground surface, in a straight line pointing towards the volcano. The 24 channels were sampled at 250 Hz, and data acquisition was performed in real-time and continuously till the end of the eruption with occasional minor gaps. The resulting seismoacoustic dataset is a sample of elastic energy propagating in both the subsurface and the atmosphere, allowing us to improve our understanding of the eruptive subsurface and subaerial processes. We use these seismoacoustic records to identify and characterize the different phases and signals of the volcanic activity. For the first analysis of the dataset we performed the calculation and graphing of spectrograms during the acquisition. We identify eruptive signals and correlate them with different events that can be directly observed on the basis of frequency content and relative timing. Explosive events like those derived from destruction of conduit plugs and ash-rich plumes emission, ash-rich explosions, volcanic lightning and degassing events are being analysed.

Finally, we study the correlation of seismic and seismoacoustic records for the same event by comparing with seismic data recorded on land stations. Results show that a good correlation exists between seismic and seismo-acoustic data for the main activity observed in the surface: the activity at the various vents and events like episodes of ash emission and bursts, indicating that this methodology can be successfully applied to monitor remote eruptions. Coupled seismoacoustic observations have turned out to be useful because they provide a comprehensive record of subsurface and subaerial eruptive activity.

How to cite: Jurado, M. J., Lopez, C., Blanco, M. J., Lopez, R., Meletlidis, S., and Moure, D.: Seismoacoustic monitoring of La Palma 2021 volcanic eruption (Canary Islands): first results, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11086, https://doi.org/10.5194/egusphere-egu22-11086, 2022.

Geodesy
09:36–09:42
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EGU22-12844
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On-site presentation
Claudio De Luca, Emanuela Valerio, Flora Giudicepietro, Giovanni Macedionio, Francesco Casu, and Riccardo Lanari

Since 19 September 2021, an intense eruptive activity has begun at Cumbre Vieja volcano (La Palma, Canary archipelago, Spain), causing huge social and economic damage. The eruption was preceded and accompanied by several phenomena, such as ground deformations and seismic activity. In this work, we analyse the Differential Interferometric Synthetic Aperture Radar (DInSAR) measurements obtained by processing Sentinel-1 images acquired from both ascending and descending orbits, in order to quantify the retrieved pre- and co-eruptive deformation patterns. In particular, we exploit the Advanced DInSAR technique referred to Parallel-Small BAseline Subsets (P-SBAS), showing the importance for oceanic islands, such as La Palma, of investigating DInSAR products retrieved from time series, instead of single interferograms. Indeed, this may allow us to effectively remove possible atmospheric artifacts within the retrieved displacement measurements. Subsequently, we invert the processed DInSAR measurements through analytical modelling with the aim of examining the characteristics of the volcanic sources responsible for the observed deformations. In detail, our results highlight that a sill-like source was active in the pre-eruptive phase (8 – 16 September) and it can be interpreted as the effect of the temporary accumulation of magma during its transport toward the surface. On the other hand, the action of two dikes prevailed during the co-eruptive phase (17 – 22 September), causing the eruptive vent opening. Therefore, our results suggest that a complex network of sills and dikes has allowed the magma rising. Moreover, our findings are in good agreement with the seismicity recorded by the Instituto Geografico Nacional (IGN) network, and several geophysical evidences (i.e., resistivity anomaly, petrographic analyses, computation of the erupted magma volumes, field observations).

How to cite: De Luca, C., Valerio, E., Giudicepietro, F., Macedionio, G., Casu, F., and Lanari, R.: The September 2021 eruption at Cumbre Vieja volcano (La Palma, Canary Islands): investigation on the pre- and co-eruptive phases through DInSAR measurements and analytical modelling, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12844, https://doi.org/10.5194/egusphere-egu22-12844, 2022.

09:42–09:48
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EGU22-7341
Time evolution of the magmatic intrusion below La Palma before eruption
(withdrawn)
Jose Fernandez, Joaquin Escayo, Antonio G. Camacho, Mimmo Palano, Juan F. Prieto, Zhongbo Hu, Sergey V. Samsonov, Kristy F. Tiampo, and Eumenio Ancochea
09:48–09:54
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EGU22-4943
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Highlight
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Virtual presentation
Pablo J. Gonzalez, María Charco, Yu Jiang, Antonio Eff-Darwich, Eugenio Sansosti, Diego Reale, Yu Morishita, Hiroshi Munekane, and Tomokazu Kobayashi

Reservoirs accumulate and evolve magma during decades to centuries under Canary Islands volcanoes. Finally, magma migrates towards the surface before eruptions. However, little is known about the pathways and mechanisms controlling this migration. Past low eruption recurrence rate and the fact that the most recent 2011-2012 El Hierro eruption was off-shore hampered us to fully understand the magma(s) migration process. During the 2021 Cumbre Vieja eruption eruptible magmas showed remarkable mobility during the preceding 8 days before the eruption on the 13th of September 2021. This magma migration was reflected as surface ground deformation and seismicity. We used satellite radar interferometry to track 1) the geometry of the active magmatic reservoirs, and 2) the dynamics of magma emplacement and migration. To further, speculate about the reasons for that geometry and dynamics. Hence, the 2021 Cumbre Vieja eruption represents a unique opportunity to learn more about the mechanisms that facilitate magma migration beneath these volcanoes, and compare it with similar basaltic volcanoes. Our work aims to contribute knowledge that will help hazard assessment and volcanic risk reduction. 

How to cite: Gonzalez, P. J., Charco, M., Jiang, Y., Eff-Darwich, A., Sansosti, E., Reale, D., Morishita, Y., Munekane, H., and Kobayashi, T.: The hows and whys of pre-eruptive magma migration before 2021 Cumbre Vieja eruption, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4943, https://doi.org/10.5194/egusphere-egu22-4943, 2022.

09:54–10:00
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EGU22-10465
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Highlight
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Virtual presentation
Elena González-Alonso, Héctor Lamolda, Francisco Quirós, Antonio Jesús Molina, Anselmo Fernández-García, Laura García-Cañada, Jorge Pereda de Pablo, Jorge Domínguez-Valbuena, Fernando Prieto-Llanos, and Lucía Sáez-Gabarrón

Surface deformation is considered one of the most important parameters in volcano monitoring. That was shown during the recent Cumbre Vieja eruption (La Palma, Canary Islands) which started on 19th September 2021 and lasted almost three months. Several days after the beginning of the unrest, on 11th September, deformation data were able to confirm the depth of the volcanic intrusion and constrain an approximate volume.Maximum deformation of 20 cm were measured prior to the beginning of the eruption pointing to the area were the dike finally reached the surface. 

After the eruption onset, deformation monitoring resulted essential to understand eruption dynamics. This work is focused on results obtained by the geodetic techniques operated by Instituto Geográfico Nacional (IGN) during the three months of volcanic activity.  This system includes GNSS permanent stations, InSAR processing, tiltmeters and a GNSS-RTK periodic measurements on benchmarks around Cumbre Vieja. It allowed to measure displacements with different temporal and spatial scales providing a complete picture of the deformation, which, together with other geophysical parameters, helped to manage the volcanic crisis and interpret the magmatic processes.

How to cite: González-Alonso, E., Lamolda, H., Quirós, F., Molina, A. J., Fernández-García, A., García-Cañada, L., Pereda de Pablo, J., Domínguez-Valbuena, J., Prieto-Llanos, F., and Sáez-Gabarrón, L.: Combination of geodetic techniques for deformation monitoring during 2021 La Palma eruption  , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10465, https://doi.org/10.5194/egusphere-egu22-10465, 2022.

Coffee break
Chairpersons: Carmen López Moreno, Luca D&#39;Auria
Other Geophysics
10:20–10:26
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EGU22-5225
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ECS
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Virtual presentation
David Martínez van Dorth, Perla Piña-Varas, Iván Cabrera-Pérez, Juanjo Ledo, Luca D'Auria, and Nemesio Pérez

Geophysical monitoring is essential to understand the activity and behaviour of volcanoes, especially when new or unusual signs are detected. Monitoring would help to address critical issues, such as the evolution of the magma at depth, which is of particular interest when the volcanic event takes place in populated areas.  Among the geophysical methods, the electromagnetic ones have not been widely used in volcanic monitoring. However, these methods are very sensitive to the presence of fluids and therefore, to the presence of magma, since this will have a significant impact on the electrical resistivity of the subsoil.

Thus, after the onset of the volcanic eruption that began on September, 19, 2021 in the Cumbre Vieja area, on the island of La Palma (Canary Islands), several magnetotelluric stations were installed to perform a volcanic monitoring experiment. The different geophysical stations were installed in the surroundings of the volcanic edifice, as well as in those areas where the epicenters of the major seismic swarms were located. Magnetotelluric stations have been installed for continuous monitoring, recording electric and magnetic fields in the N-S and E-W directions. According to the quality of the data, we have obtained transfer functions for the period range of 0.001 - 100 s.

The aim of this experiment is to analyze the possible variations of the apparent resistivity and phase curves in time. In addition, the electrical resistivity model of the island published in 2020 will be compared with the seismicity that has been occurring since the beginning of the volcanic crisis.

The first preliminary results show slight changes in time and, in comparison with the previous data, this could be related to magmatic movements at depth. Furthermore, the comparison of the seismicity with the previous electrical resistivity model shows that most of the epicenters are located outside the clay cap. This epicenter-resistivity structure relationship is highlighting the considerable difference in the behavior of the clay layer and the surrounding rocks, which is somewhat validating the resistivity model and its interpretation.

How to cite: Martínez van Dorth, D., Piña-Varas, P., Cabrera-Pérez, I., Ledo, J., D'Auria, L., and Pérez, N.: Electromagnetic monitoring of the Cumbre Vieja eruption (La Palma, Canary Islands), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5225, https://doi.org/10.5194/egusphere-egu22-5225, 2022.

10:26–10:32
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EGU22-8273
Perla Piña-Varas, Juanjo Ledo, David Martínez van Dorth, Pilar Queralt, Iván Cabrera Pérez, Luca D’Auria, and Nemesio Pérez

The recent eruption in La Palma (September 19th-December 14th, 2021) represents a unique opportunity to assess the effect of the magma on the electrical resistivity distribution of the subsoil. On the one hand, the presence of magma generates strong resistivity contrasts with the hosting units, since magmas contain dissolved water in their composition that reduces its resistivity. On the other hand, a 3-D resistivity model of La Palma Island was performed in 2019, proving us with a baseline model.

Several electromagnetic experiments have been performed in the island since the beginning of the volcanic eruption, in order to understand the changes of the resistivity associated to the magma intrusion, as well as the potential of these methods for the volcanic monitoring.

Here, we present in the frame of PIXIL project some preliminary results of a set of tests conducted against the 3-D resistivity model of the island (baseline model), to determine the characteristics of the detectable magmatic body at depth with the magnetotelluric data available. Understanding the extension, geometry, pathway, etc. of the magma is essential since many volcanic hazards are related to the size and depth of the sources of magma, especially in La Palma Island which is one of the highest potential risks in the Canary Islands.

How to cite: Piña-Varas, P., Ledo, J., Martínez van Dorth, D., Queralt, P., Cabrera Pérez, I., D’Auria, L., and Pérez, N.: Magma effect on the electrical resistivity: La Palma (Canary Islands), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8273, https://doi.org/10.5194/egusphere-egu22-8273, 2022.

10:32–10:38
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EGU22-8052
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ECS
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Highlight
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Virtual presentation
Caron E.J. Vossen, Corrado Cimarelli, Valeria Cigala, Ulrich Kueppers, José Barrancos, Isabella Haarer, Markus Schmid, Wolfgang Stoiber, Luca D’Auria, Germán Padilla, Pedro Hernández, and Nemesio Pérez

Volcanic lightning is a common phenomenon observed during explosive eruptions of high magnitude and intensity. Lightning observations in milder explosive eruptions, generally of basaltic composition, are less frequent, arising the question of whether electrification may be a common feature over the whole spectrum of explosive styles and magma compositions.

The 2021 eruption of Cumbre Vieja on the island of La Palma (Canary Islands, Spain) started on 19 September 2021, continuously producing lava flows and tephra of average basanite to tephrite composition during 85 consecutive days, eventually generating a >200 m tall scoria cone (about 1220 m a.s.l.) and a vast compound lava flow field. Lightning was frequently observed in the plume during different phases of the explosive activity. This eruption provided the rare opportunity to monitor variations in the electrical activity on various time scales continuously over several weeks. We measured such electrical activity using a lightning detector operating in the extremely low frequency range with a sample rate of 100 Hz (Vossen et al., 2021), installed about 2 km away from the active vents. The detector was deployed on 11 October 2021 and recorded continuously until the end of the eruption on 13 December 2021, thus providing a unique dataset of its kind.

Lightning activity varied during the eruption with alternating hours-long periods of high intensity continuous lightning production as well as minutes-long isolated episodes with interposed periods of quiet. Stable fair-weather conditions over La Palma recorded by meteorological stations during the whole eruption (exception made for a thunderstorm episode on 26 November 2021), allow a confident attribution of the changeable lightning activity to the explosive activity of the scoria cone. Here, we present volcanic lightning and electrification timeseries as a function of the varying explosive activity as observed through thermal videography and acoustic recordings (Cigala et al., 2022).

 

Vossen, C. E. J., Cimarelli, C., Bennett, A. J., Geisler, A., Gaudin, D., Miki, D., Iguchi, M., and Dingwell, D. B. (2021). Long-term observation of electrical discharges during persistent Vulcanian activity. Earth Planet. Sci. Lett., 570, 117084. https://doi.org/10.1016/j.epsl.2021.117084.

How to cite: Vossen, C. E. J., Cimarelli, C., Cigala, V., Kueppers, U., Barrancos, J., Haarer, I., Schmid, M., Stoiber, W., D’Auria, L., Padilla, G., Hernández, P., and Pérez, N.: Electrical activity of the 2021 Cumbre Vieja eruption, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8052, https://doi.org/10.5194/egusphere-egu22-8052, 2022.

Geochemistry
10:38–10:44
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EGU22-5603
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Virtual presentation
Violeta T. Albertos, Guillermo Recio, Mar Alonso, Cecilia Amonte, Fátima Rodríguez, Claudia Rodríguez, Lia Pitti, Victoria Leal, Germán Cervigón, Judith González, Monika Przeor, José Manuel Santana-León, José Barrancos, Pedro A. Hernández, Germán D. Padilla, Gladys V. Melián, Eleazar Padrón, María Asensio-Ramos, and Nemesio M. Pérez

Cumbre Vieja is the most active volcano of the Canary Islands since it has been the scenario of  8 of 17 historical eruptions in this archipelago. A recent magmatic reactivation started at Cumbre Vieja volcano on October 2017, and 9 additional seismic swarms occurred until the recent eruption which started on September 19, 2021, and ended on December 13, 2022 after 85 days of eruption. Since the first day of the eruption, extending to current days, INVOLCAN performed the monitoring of SO2 realesed by this eruption using a miniDOAS on terrestrial (car), sea (ship) and air (helicopter) mobile position. More than 360 measurements of SO2 emission rates were carried out daily. The standard deviation of the estimated values obtained daily was ~ 20%. During the first days of the eruption, estimated SO2 emission rates reached more than 30,000 tons/day, and maintaining weekly average values above 10,000 tons/day until the end of the eruption. After a final paroxysmal phase with an eruptive column of 8,500 m altitude, decreased significantly to averages values of 250 tons/day. Estimated SO2 emission rates from the 2021 Cumbre Vieja eruption became a powerful tool to contribute to the understanding of eruptive dynamics.

How to cite: Albertos, V. T., Recio, G., Alonso, M., Amonte, C., Rodríguez, F., Rodríguez, C., Pitti, L., Leal, V., Cervigón, G., González, J., Przeor, M., Santana-León, J. M., Barrancos, J., Hernández, P. A., Padilla, G. D., Melián, G. V., Padrón, E., Asensio-Ramos, M., and Pérez, N. M.: Sulphur dioxide (SO2) emissions by means of miniDOAS measurements during the 2021 eruption of Cumbre Vieja volcano, La Palma, Canary Islands, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5603, https://doi.org/10.5194/egusphere-egu22-5603, 2022.

10:44–10:50
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EGU22-12201
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On-site presentation
Catherine Hayer, José Barrancos, Mike Burton, Fátima Rodríguez, Ben Esse, Pedro Hernández, Gladys Melián, Eleazar Padrón, María Asensio-Ramos, and Nemesio Pérez

Volcanic gas emissions are an integral part of volcano monitoring around the world and can be interpreted to understand the state of a volcano and the evolution of an individual eruption. The low ambient concentrations of SO2 make it an ideal monitoring candidate.

Throughout the 2021 eruption of Cumbre Vieja, La Palma (Spain), observations of SO2 emissions were made using ground-based instruments, in transverse mode, static scanners and on-board drones, as well as by numerous satellite instruments. Direct comparison between satellite- and ground-based instruments is always challenging, but the long duration of the eruption and repeated measurements from both data sets made this a good candidate.

Data from the Sentinel-5P instrument TROPOMI was combined with the PlumeTraj back-trajectory analysis toolkit to produce sub-daily SO2 fluxes that can be directly compared to the ground-based observations as well as other geophysical and geochemical monitoring data.

The volcano produced significant volcanic ash emissions, particularly in the earlier phases of the eruption, which impacted both ground- and satellite-based measurements. This produced underestimations in the SO2loading where ash was present, impacting the proximal plume more that the distal as the ash settles out with time. This meant that traverse measurements were more impacted, leading to a disparity in the measured fluxes from ground and space. Later, when ash emissions had decreased, the agreement between the two was much improved, with trends closely replicated between the traverse and satellite fluxes.

The initial estimates of the total SO2 emission from the eruption were 4.1 Mt from TROPOMI and 1.2 Mt from the traverse data.

These measurements formed part of the official monitoring effort, providing insights into the eruption’s evolution and informing the civil defence response throughout the eruption.

How to cite: Hayer, C., Barrancos, J., Burton, M., Rodríguez, F., Esse, B., Hernández, P., Melián, G., Padrón, E., Asensio-Ramos, M., and Pérez, N.: From up above to down below: Comparison of satellite- and ground-based observations of SO2 emissions from the 2021 eruption of Cumbre Vieja, La Palma, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12201, https://doi.org/10.5194/egusphere-egu22-12201, 2022.

10:50–10:56
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EGU22-5629
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Highlight
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On-site presentation
Mike Burton, Alessandro Aiuppa, María Asensio-Ramos, Alessandro La Spina, Patrick Allard, Emma Liu, Vittorio Zanon, Ana Pardo Cofrades, José Barrancos, Kieran Wood, Marcello Bitetto, Eleazar Padrón, Joao Pedro Lages, Catherine Hayer, Klaudia Cyrzan, Federica Schiavi, Estelle Rose-Koga, Pedro Hernández, Luca D'Auria, and Nemesio Pérez

Mafic alkali-rich magmas, such as those which form the Canary Islands, Spain, have been proposed as being CO2-rich due to low-degree partial melting and the presence of recycled oceanic crust in the mantle source region. A CO2-rich mantle source of Canary magmas has been suggested from melt inclusions study of the 2011 submarine El Hierro eruption, but this has not been verified yet by directly measuring magmatic CO2 emissions during a subaerial eruption as the last such event in the archipelago, in 1971, occurred before the advent of modern gas sensing tools. Here we report on the first results for gas emissions from the

2021 eruption of Cumbre Vieja on La Palma island. We determined the chemical composition and mass flux of magmatic degassing during both effusive and explosive activities by combining direct plume measurements with MultiGas sensors from the ground, UAV and helicopter, OP-FTIR remote sensing and satellite-based (TROPOMI) SO2 flux quantification based on back-trajectory modelling. Degassing mass budgets and the magma volatile concentrations were then derived from microprobe analysis of olivine-hosted melt inclusions and comparing our gas results with best estimates of the magma extrusion rates during both explosive and effusive activities. Based on this approach we obtain a direct quantification of the initial CO2 content of the magma and of the exsolved pre-eruptive CO2 gas phase that fed the Cumbre Vieja eruption.

We find unprecedentedly high CO2 content in the mantle source of La Palma magma, consistent with high volatile contents predicted from petrological analyses. Eruptions of oceanic island alkali-rich magmas produce disproportionately high CO2 emissions, highlighting the key role mantle heterogeneity plays in determining the impact of intraplate volcanism.

How to cite: Burton, M., Aiuppa, A., Asensio-Ramos, M., La Spina, A., Allard, P., Liu, E., Zanon, V., Pardo Cofrades, A., Barrancos, J., Wood, K., Bitetto, M., Padrón, E., Lages, J. P., Hayer, C., Cyrzan, K., Schiavi, F., Rose-Koga, E., Hernández, P., D'Auria, L., and Pérez, N.: CO2-rich emissions from alkalic magmatism in the Canary Islands, Spain, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5629, https://doi.org/10.5194/egusphere-egu22-5629, 2022.

10:56–11:02
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EGU22-10266
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ECS
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On-site presentation
Ana Pardo Cofrades, Mike Burton, María Asensio-Ramos, José Barrancos, Alessandro La Spina, Patrick Allard, Catherine Hayer, Benjamin Esse, Pedro A. Hernández, Eleazar Padrón, Gladys V. Melian, and Nemesio M. Peréz

On September 19th 2021 a fissure eruption started on the Cumbre Vieja rift on La Palma, Canary Islands. The fissure eruption rapidly evolved into a cone-forming eruption, with several summit vents producing explosive activity and lava jetting, while lava spattering and effusive activity occurred at/from lower flank vents.

We used open-path Fourier transform infrared spectroscopy (OP-FTIR) to measure the chemical composition of degassing associated with both explosive and effusive activities, using absorption spectra of the radiation emitted by molten lava and incandescent ash. Measurements were performed daily since October 2nd until the end of the eruption (mid-December), from different sites and at distance range of 0.6 to 5 km from the vents. They allowed us to retrieve the molar proportions of H2O, CO2, SO2, HCl and CO in gas emissions from the different vents and different activities.

In this work, we report the main results obtained for the gas compositions, their spatial and temporal evolution during the eruption, the influence of fragmentation (ash) on the degassing of HCl, and the gas-magma redox state during the La Palma 2021 eruption.

How to cite: Pardo Cofrades, A., Burton, M., Asensio-Ramos, M., Barrancos, J., La Spina, A., Allard, P., Hayer, C., Esse, B., Hernández, P. A., Padrón, E., Melian, G. V., and Peréz, N. M.: Insights into magma degassing processes during the 2021 Cumbre Vieja eruption, La Palma, from open-path FTIR spectroscopy, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10266, https://doi.org/10.5194/egusphere-egu22-10266, 2022.

11:02–11:08
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EGU22-9629
Fátima Rodríguez, Nemesio M. Pérez, Cecilia Amonte, Alba Martín-Lorenzo, Gladys V. Melián, Beverly C. Coldwell, Matthew J. Pankhurst, María Asensio-Ramos, Pedro A. Hernández, and Eleazar Padrón

On September 19, 2021, a new eruption began at the west flank of Cumbre Vieja volcano (La Palma, Canary Islands), after an inter-eruptive period of 50 years from the previous eruption (Teneguía, October 1971). The 2021 event was a fissure and powerful strombolian eruption with a magnitude VEI=3 and it has been considered as the most important eruption of Europe during the last 75 years in terms of the significant amount of SO2 released and the serious damage caused by the lava flows.

In this work we report the leachate analyses of volcanic ash from the beginning of the eruption, focused on determining the relationship between chemical composition of water‐soluble components adhering to volcanic ash and the volcano’s activity episodes. A total of 5 main control sites or ash-collecting stations were established and ash was picked up in a daily basis. These were located around the main eruptive vents at different distances. Water-extractable concentrations of the samples leached at 1:25 for 2 hours were analyzed by ion chromatography (Cl-, SO42-, F-, Br-, NO3-, Na+, Ca2+, Mg2+, K+) and ICP-MS (Li, B, Al, Si, Sr, Ba, Fe, Ti, Cu, Sb, Rb, Ni, Co, Cd, V). The most abundant components in the leachates were SO42- for the anions and Na+ for the cations, with mean concentrations of 854 and 455 mg/kg, respectively. The results showed the following trend, in decreasing order of abundance: SO4-2>Na+>Cl->F->Ca2+>Al3+>K+>Mg2+. Fluoride, an element of primary concern for human and animal health, showed a range of 16 and 733 mg/kg and an average of 239 mg/kg, which is relatively higher than global median value (129 mg/kg). The S/Cl molar ratio in the ash leachate presented a ranged of values from 0.16 to 5.9 and the observed values > 3.0 seems to be related to ash-rich phases of the eruption. Preliminary results show significant temporal variations in ash leachate compositions, revealing changes in the eruption dynamics.

How to cite: Rodríguez, F., Pérez, N. M., Amonte, C., Martín-Lorenzo, A., Melián, G. V., Coldwell, B. C., Pankhurst, M. J., Asensio-Ramos, M., Hernández, P. A., and Padrón, E.: Geochemistry of ash leachates during the 2021 eruption of Cumbre Vieja volcano, La Palma, Canary Islands, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9629, https://doi.org/10.5194/egusphere-egu22-9629, 2022.

11:08–11:14
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EGU22-11371
Pedro Antonio Torres González, Natividad Luengo Oroz, Ángel David Moure García, Lucía Sáez Gabarrón, Víctor Villasante Marcos, Rubén López Díaz, Carlos Cecilio Rodríguez López, Walter D'Alessandro, Luís Pujol, and Fausto Grassa

In 2017, La Palma Island entered a state of volcanic unrest, with nine pre-eruptive seismic swarms detected by the seismic monitoring network of the Instituto Geográfico Nacional (IGN) up to 2021, most of the events occurring at depths of 20-35 km. During this period, the IGN geochemical network detected significant changes in deep gas emissions. On 11 September 2021, the last and most energetic pre-eruptive unrest began with more than 1500 earthquakes located at 10-15 km depth and migrating upwards, accompanied by ground deformation with up to ~20 cm vertical inflation detected by the IGN deformation network (GNSS, Insar, tiltmeters). On 19 September 2021 at 15:08 UTC, a volcanic eruption began on the western flank of Cumbre Vieja in El Paso village. This was the first eruption in the island after 50 years of quiescence.

The 2021 eruption has lasted almost three months, ending on 13-14 December 2021 (last activity at the time of this writing). It began as a SE-NW fissural eruption and rapidly evolved to construct a main volcanic edifice up to ~200 m high, with several craters partially overlapping in a SE-NW direction, and later it constructed a secondary cone with a horseshoe shape open to the NE. The eruptive activity has been both strombolian and effusive, sometimes alternating and many times simultaneous with different behaviour at different emission points, a typical situation being strong degassing and strombolian jet and ash emission from an upper crater simultaneous to emission of fluid lavas and lava lake formation and periodical overflowing from a lower crater. Significant volcanic plumes have reached up to 8500 masl (typical value of 3000-3500 masl), and a large set of successive basanitic lava flows has been emitted to the west, developing a volcanic lava-fan covering ~12 km2 (~3000 buildings) and reaching the sea at several points along the western coast of La Palma.

During the eruption, the IGN geochemical monitoring network included four stations measuring diffuse radon/thoron in soil, one station measuring diffuse CO2 flux in soil, an infrared thermal camera coupled with a visual camera and six water sampling points, regularly sampled for water composition, dissolved radon content, total and isotopic composition of dissolved gas (5 points) and free gas (1 point). Physical-chemical parameters (pH, Eh, T, EC, alkalinity) were also regularly measured in situ at these points. In this work we present the obtained dataset and first results. Changes in dissolved gas, mainly H2 and He, were recorded before and during the eruption. In two radon/thoron stations, abrupt increases in both gaseous species related to the eruptive process were also detected. Changes in dissolved radon in water were also observed at some of the sampling points. Finally, the analysis of the thermal image set can be used to monitor the surface volcanic activity in correlation with visual images and geophysical signals (volcanic tremor).

How to cite: Torres González, P. A., Luengo Oroz, N., Moure García, Á. D., Sáez Gabarrón, L., Villasante Marcos, V., López Díaz, R., Rodríguez López, C. C., D'Alessandro, W., Pujol, L., and Grassa, F.: Geochemical monitoring of the volcanic unrest and the eruption in La Palma island (Canary Islands, Spain): the 2017-2021 dataset and first results, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11371, https://doi.org/10.5194/egusphere-egu22-11371, 2022.

Volcanology
11:14–11:24
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EGU22-8773
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solicited
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On-site presentation
José Manuel Santana de León, Gladys V. Melián, Claudia Rodríguez, Germán Cervigón-Tomico, Victor Ortega, David Martínez van Dorth, Iván Cabrera-Pérez, María Cordero, Monika Przeor, Rui Filipe Fagundes Silva, Sandro Branquinho de Matos, Eleonora Baldoni, Maria Margarida Pires Ramalho, Fátima Viveiros, David Calvo, and Nemesio M. Pérez

On September 19, 2021, a volcanic eruption began at the west flank of Cumbre Vieja, La Palma, the most northwestern of the Canary Islands. The lava flows caused the evacuation of thousands of residents living in the vicinity of the volcano, and 1,219 hectares were covered by lava flows. After 85 days of activity, the eruption ended on December 13, 2021. Since visible volcanic gas emissions (fumaroles, hot springs, etc.) do not occur at the surface environment of Cumbre Vieja, the geochemical program for the volcanic surveillance has been focused mainly on diffuse (non-visible) degassing studies. Since 2001, diffuse CO2 emission surveys have been yearly performed in summer periods to minimize the influence of meteorological variations. Measurements of soil CO2 efflux have been performed following the accumulation chamber method in about 600 sites and spatial distribution maps have been constructed following the sequential Gaussian simulation (sGs) procedure to quantify the diffuse CO2 emission from the studied area. In the period 2001-2016, the diffuse CO2 output released to the atmosphere from Cumbre Vieja volcano ranged between 320 to 1,544 t·d-1. During pre-eruptive period (2016-2021), time series of the diffuse CO2 emission showed a change with an increasing trend from 788 t·d-1 up to 1,870 t·d-1, coinciding with the beginning of the seismic swarms. This increase of diffuse CO2 emission is interpreted as a geochemical precursory signal of volcanic eruption of Cumbre Vieja, on September 19, 2021. The observed increase on the diffuse CO2 emission during this time window suggests that in October 2017 a process of magma ascent began from the upper mantle to depths between 35-25 km, at which the seismic swarms were recorded for four years. During eruption period, diffuse CO2 emission showed strong temporal variations with a minimum value of the diffuse CO2 emission in October 21, followed by an increase trend of up to 4,435 t·d-1 on December 14, the highest of time series and coinciding with the end of the eruption. During the post-eruptive period, the diffuse CO2 emission has shown a descending trend. Our results demonstrate that periodic surveys of diffuse CO2 emission are extremely important in the volcanic surveillance tools of Cumbre Vieja to improve the detection of early warning signals of future volcanic unrest episodes.

 

 

 

How to cite: Santana de León, J. M., Melián, G. V., Rodríguez, C., Cervigón-Tomico, G., Ortega, V., Martínez van Dorth, D., Cabrera-Pérez, I., Cordero, M., Przeor, M., Silva, R. F. F., Matos, S. B. D., Baldoni, E., Ramalho, M. M. P., Viveiros, F., Calvo, D., and Pérez, N. M.: Long-term variations of diffuse CO2 at Cumbre Vieja volcano, La Palma, Canary Islands, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8773, https://doi.org/10.5194/egusphere-egu22-8773, 2022.

11:24–11:30
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EGU22-9819
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ECS
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On-site presentation
Claudia Rodríguez-Pérez, José Barrancos, Pedro A. Hernández, Nemesio M. Pérez, Eleazar Padrón, Gladys V Melián, Fátima Rodríguez, María Asensio-Ramos, and Germán D. Padilla

Cumbre Vieja volcano is the last stage in the geological evolution of La Palma Island (Canarian Archipelago, Spain). The volcanic activity of La Palma has taken place exclusively in Cumbre Vieja in the last 123 ka, and has remained in volcanic quiescence in the last 50 years. After the occurrence of several seismic seismic swarms since 2017, a volcanic eruption began at Cumbre Vieja volcano on September 19, 2021, and resulted in the longest volcanic event since data are available on the island. The eruption lasted for 85 days and 8 hours and lava flows covered 1,219 hectares. As part of the volcano monitoring program of Cumbre Vieja, diffuse degassing of CO2 has been continuously monitored since 2005 at the southernmost part of Cumbre Vieja according to the accumulation chamber method. The monitoring site (LPA04) was selected because it shows anomalous diffuse CO2 degassing emission values with respect to the background values that had been measured in different surveys (Padrón et al., 2015). Meteorological and soil physical variables are also measured in an hourly basis and transmitted to ITER facilities about 150 Km far away. Since its installation, CO2 emissions ranged from non-detectable (<1.5 gm-2d-1) to 1,464.0 gm-2d-1. The time series was characterized by a strong variability in the measured values that are modulated mainly by the atmospheric and soil parameters. Soil moisture is the monitored parameter that explains the highest variability of the data, being the dry season (spring y summer) the period with the highest observed diffuse emission values. This behavior in the time series changed after 2017 as an increasing trend was observed in a good temporal agreement with the increase of seismic activity recorded. Diffuse CO2 emission values showed a sustained increase reaching maximum values (up to 890 gm-2d-1) before de eruption onset. The observed diffuse CO2 emissions trend in the LPA04 geochemical station was useful to record the arrival of magmatic CO2 due to the occurrence of an upward magma migration beneath La Palma Island that caused the 2021 eruptive event.

Padrón et al., (2015). Bull Volcanol 77:28. DOI 10.1007/s00445-015-0914-2

How to cite: Rodríguez-Pérez, C., Barrancos, J., Hernández, P. A., Pérez, N. M., Padrón, E., Melián, G. V., Rodríguez, F., Asensio-Ramos, M., and Padilla, G. D.: Continuous monitoring of diffuse CO2 emission from Cumbre Vieja volcano: early evidences of magmatic CO2 surface arrival, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9819, https://doi.org/10.5194/egusphere-egu22-9819, 2022.

11:30–11:36
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EGU22-6345
Gladys Melián, Ana Meire, Cecilia Amonte, Lia Pitti Pimienta, Daniel Di Nardo, Mar Alonso, Maud Smit, Victoria Leal, Rubén García-Hernández, William Hernández, Sonia M.M. Pereira, Simone Aguiar, Leticia Ferrera, and Nemesio M. Pérez

La Palma Island (708 km2) is located at the north-west and is one of the youngest (~2.0My) of the Canarian Archipelago. On September 19, 2021, a new volcanic eruption occurred at Cumbre Vieja volcanic system at the southern part of the island, the most active basaltic volcano in the Canaries. The erupting fissure (~1.0 km-length) is characterized by lava effusion, strombolian activity, lava fountaining, ash venting and gas jetting. After 85 days of eruption finished on December 13, 2021. We report herein the results of an intensive soil gas study, focused on non-reactive and/or highly mobile gases such as helium (He) and hydrogen (H2), in Cumbre Vieja. He has unique characteristics as a geochemical tracer: it is chemically inert and radioactively stable, non-biogenic, highly mobile and relatively insoluble in water. H2 is one of the most abundant trace species in volcano-hydrothermal systems and is a key participant in many redox reactions occurring in the hydrothermal reservoir gas. Since 2002, soil gas samples were regularly collected at ~40 cm depth using a metallic probe at 600 sites for each survey. He content was analysed by means of a quadrupole mass spectrometer (QMS; Pfeiffer Omnistar 422 and HIDEN QGA) and H2 concentrations by a micro-gas chromatograph (microGC; VARIAN CP490). Spatial distribution maps have been constructed following the sequential Gaussian simulation (sGs) procedure to quantify the diffuse He and H2 emission from the studied area. The time series of both diffuse He and H2 emission show significant increases before and during the occurrence of seismic swarms that took place in the period 2017-2021. During the eruptive period, significant increases in diffuse He and H2 emission were also observed with good temporal agreement with the increase of the volcanic tremor. These increases in diffuse He and H2 emission preceded the peak of diffuse CO2 emission as expected by the characteristics of these gases. The absence of visible volcanic gas emissions (fumaroles, hot springs, etc.) at the surface environment of Cumbre Vieja, makes this type of studies in an essential tool for volcanic surveillance purposes.

 

How to cite: Melián, G., Meire, A., Amonte, C., Pitti Pimienta, L., Di Nardo, D., Alonso, M., Smit, M., Leal, V., García-Hernández, R., Hernández, W., Pereira, S. M. M., Aguiar, S., Ferrera, L., and Pérez, N. M.: Diffuse He and H2 emissions from Cumbre Vieja volcano before and during the recent eruption, La Palma, Canary Islands, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6345, https://doi.org/10.5194/egusphere-egu22-6345, 2022.

11:36–11:42
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EGU22-9349
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Virtual presentation
Eleazar Padrón, Nemesio M. Pérez, Gladys V. Melián, Hirochika Sumino, María Asensio-Ramos, Pedro A. Hernández, Claudia Rodríguez, José H. Lorenzo, Guillermo Recio, Mar Alonso, Fátima Rodríguez, and Luca D’Auria

A volcanic eruption began at Cumbre Vieja volcano (La Palma, Canary Islands, Spain) on September 19, 2021, and resulted in the longest volcanic event since data are available on the island: it finished after 85 days and 8 hours of duration and 1,219 hectares of lava flows. This volcanic eruption is part of the volcanic evolution of La Palma Island, the fifth in extension (706 km2) and the second in elevation (2,423 m a.s.l.) of the Canarian archipelago. Cumbre Vieja volcano, where the volcanic activity has taken place exclusively in the last 123 ka, forms the southern part of the island. The first geophysical precursory signals of the last eruptive process, started on October 7th and 13rd, 2017, when two remarkable seismic swarms interrupted a seismic silence of 46 years in Cumbre Vieja volcano with earthquakes located beneath Cumbre Vieja volcano at depths ranging between 14 and 28 km with a maximum magnitude of 2.7. Five additional seismic swarms were registered in 2020 and four in 2021, the last being the one that preceded the eruption, beginning a week before it. 3He/4He ratio has been monitored at Dos Aguas cold mineral spring in La Palma Island since 1991 to date as an important volcano monitoring tool able to provide early warning signal of future volcanic unrest episodes, as magmatic helium emission studies have demonstrated to be sensitive and excellent precursors of magmatic processes occurring at depth. A significant increase was observed from 2011 to 2012, when the 3He/4He ratio reached the highest value of the period 1991-2019: 10.24 RA (being RA the ratio in atmospheric helium) in September 2012. At that time, this was the highest 3He/4He ratio reported from the Canarian archipelago measured either in the lavas or terrestrial fluids (Padrón et al., 2015). We suggest the occurrence of aseismic magma rising episodes beneath La Palma within the upper mantle towards an ephemeral magma reservoir in the period 2011-2012. Later, in the period 2017-2020, magma rising continued and produced seismic swarms that were accompanied also by the highest 3He/4He ratio measured at Dos Aguas (September, 2020). In 2021, 3He/4He ratio decreased ~0.32 RAsince the beginning of the year, including the eruptive period.  3He/4He ratio values suggest that upward magma migration that caused the 2021 Cumbre Vieja eruption likely started in or before 2012.

Padrón et al., (2015). Bull Volcanol 77:28. DOI 10.1007/s00445-015-0914-2

How to cite: Padrón, E., Pérez, N. M., Melián, G. V., Sumino, H., Asensio-Ramos, M., Hernández, P. A., Rodríguez, C., Lorenzo, J. H., Recio, G., Alonso, M., Rodríguez, F., and D’Auria, L.: Early evidence of magmatic rise through 3He/4He ratio measurements at Dos Aguas cold mineral spring, La Palma, Canary Islands, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9349, https://doi.org/10.5194/egusphere-egu22-9349, 2022.

11:42–11:48
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EGU22-12170
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Virtual presentation
Andrea L. Rizzo, Andres Sandoval-Velasquez, Federico Casetta, Theodoros Ntaflos, Alessandro Aiuppa, Mar Alonso, Eleazar Padrón, Matthew Pankhurst, and Nemesio M. Pérez

The 2021 eruption of Cumbre Vieja volcano (La Palma Island) is one of the largest natural disasters in Europe in recent times, but also a unique opportunity for monitoring the evolution of a volcanic system and its underlying mantle source.

Geophysical and geochemical evidence suggests that volcanism in Canary Islands is driven by the presence of a mantle plume, even though helium isotopes highlight this lower mantle component (3He/4He>9 Ra) only in the Dos Aguas spring gases and the older lavas from the Taburiente caldera (north of La Palma). Conversely, fluid inclusions in lavas and spring gases from the recent Cumbre Vieja system have a MORB-like signature (8±1 Ra). These distinct signatures were ascribed to the mixing between different mantle components (Day and Hilton, 2020). In this framework, the 2021 Cumbre Vieja eruption opens new avenues to investigate the current composition of the local mantle and test the pre-existing models.

Here, we present the first insights into the 3He/4He signature of volcanic gases and phenocryst-hosted fluid inclusions from lavas erupted by the Cumbre Vieja in September-November 2021. For comparison, we analyzed the poorly evolved lavas from 1677 San Antonio eruption bearing mantle xenoliths (South of Cumbre Vieja) and a 3 Ma old picrite cropping out in the Taburiente caldera, close to the Dos Aguas spring (Day et al., 2010).

The 2021 lavas belonging to the October 27th and November 9th flows are basanite tephrites, with an average Mg# of 58.6, being more mafic than those from the September opening phase (Mg# = 50.3; Pankhurst et al., 2022). Olivine phenocrysts have Fo content mostly of mostly 78-83, and elevated Al and Cr contents. The estimated T based on the Cr and Al in olivine thermometers (DeHoog et al., 2010) is 920-960°C.

The 3He/4He ratio in phenocryst-hosted fluid inclusions from the 2021 products is 7-7.5 Ra, confirming the MORB-like signature of the volcanic products and gases dissolved in water of the Cumbra Vieja system (Day and Hilton, 2020; Torres-Gonzalez et al., 2020). Instead, the olivines in the Taburiente picrite yield 9.4±0.1 Ra, comparable to values in the Dos Aguas spring, confirming the existence of a lower mantle component below this sector of the island.

The distinct 3He/4He signature observed at Taburiente and Cumbre Vieja products is preliminary interpreted as due to either (i) small-scale heterogeneities in the local mantle, and/or (ii) a plumbing system effect that lowers the 3He/4He of the recently erupted magmas. In the latter case, magma differentiation and degassing at the crust-mantle boundary or even deeper in the mantle, coupled to the production and accumulation of radiogenic 4He, would play a central role.

REFERENCES

Day, J.M.D., et al. 2010, Geochimica et Cosmochimica Acta, v. 74, p. 6565–6589.

Day, J.M.D., Hilton, D.R., 2020. Geology.

De Hoog, J. C., Gall, L., & Cornell, D. H., 2010. Chemical Geology, 270(1-4), 196-215.

Pankhurst, M. J., et al., 2022. Volcanica, 5, 1-10.

Torres-González, P. A. et al., 2020. J. Volcanol. Geotherm. Res. 392, 106757.

How to cite: Rizzo, A. L., Sandoval-Velasquez, A., Casetta, F., Ntaflos, T., Aiuppa, A., Alonso, M., Padrón, E., Pankhurst, M., and Pérez, N. M.: First insights into the noble gas signature of the 2021 Cumbre Vieja eruption, La Palma (Canary Islands), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12170, https://doi.org/10.5194/egusphere-egu22-12170, 2022.

Lunch break
Chairpersons: Luca D&#39;Auria, Carmen López Moreno
13:20–13:26
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EGU22-8817
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On-site presentation
Victoria Leal, Cecilia Amonte, Gladys V. Melián, Ana Meire Feijoo, Daniel Di Nardo, Lía Pitti Pimienta, José M. Santana de León, Sergio Rojas, Lucía Barbero, Nemesio M. Pérez, Beverley C. Coldwell, Matthew J. Pankhurst, Fátima Rodríguez, María Asensio-Ramos, Eleazar Padrón, and Pedro A. Hernández

A recent volcanic eruption has occurred in Cumbre Vieja volcano located in the west of the La Palma Island (at the northwest of the Canary Islands) from September 19 to December 13, 2021. A total of 85 days of eruption makes it the longest volcanic event since historical data have been recorder on La Palma. This volcanic eruption is part of the last stage in the geological evolution of La Palma Island, the fifth in extension (706 km2) and the second in elevation (2,423 m a.s.l.) of the Canarian archipelago. Cumbre Vieja volcano, where the volcanic activity has taken place exclusively in the last 123 ka, forms the southern part of the island.  As a response to the occurrence of several seismic swarms and to strengthen the volcanic monitoring of Cumbre Vieja, a regular sampling of groundwater started in October 2017. Three sampling points have been selected, Las Salinas well and two horizontal galleries: Peña Horeb and Trasvase Oeste. Temperature (ºC), pH and electrical conductivity (EC, µS·cm 1) were measured in situ. Water samples were taken to measure the chemical and isotopic composition of the groundwaters in the laboratory. The temperature values showed mean values of 22.1 ºC, 23.7 ºC and 19.6 ºC for Las Salinas, Peña Horeb and Trasvase Oeste, respectively. The mean pH values were 6.50 for Las Salinas, 7.33 for Peña Horeb and 6.81 for Trasvase Oeste, while the mean E.C. values were 41,566 µS·cm-1, 1,684 µS·cm-1 and 426 µS·cm-1 for Las Salinas, Peña Horeb and Trasvase Oeste, respectively. The total alkalinity mean value of groundwater from Las Salinas well was 8.75 mEq·L-1 HCO3-, while that from Peña Horeb was 18.8 mEq·L-1 HCO3- and 4.4 mEq·L-1 HCO3- for Trasvase Oeste. The isotopic composition of O and H (δ18O and δD) showed a meteoric origin, with mean values of 0.8‰ and 7‰ vs. VSMOW for Las Salinas, -4.0‰ and -15‰ vs. VSMOW for Peña Horeb and -4.5‰ and -17 ‰ vs. VSMOW for Trasvase Oeste. Significant changes were observed during the eruptive period, likely related to interaction with endogenous gases such as CO2, H2S and H2. Regarding the isotopic composition of total dissolved carbon, expressed as δ13C-CO2, the average values were -4.6‰, -8.1‰ and -10.8‰ for Las Salinas, Peña Horeb and Trasvase Oeste, respectively, what suggests an endogenous origin for the CO2. Such deep-seated interaction seems stronger at Las Salinas. At this point, the isotopic composition of total dissolved carbon became more magmatic along the studied period, changing from an average of -3.79 in 2017-2018 to -5.17 from 2019 to 2021.Temporal variations were observed in the total alkalinity, δ13C-CO2 andδ18O and δD during the eruption period on La Palma Island. These changes observed in both chemical and isotopic composition were related to interaction between deep volcanic fluids and the groundwaters. Groundwaters studies associated to volcanic aquifers can provide important information about the magmatic gas input in the aquifer, to model groundwater circulations edifice and to strengthen the volcano monitoring.

How to cite: Leal, V., Amonte, C., Melián, G. V., Meire Feijoo, A., Di Nardo, D., Pitti Pimienta, L., Santana de León, J. M., Rojas, S., Barbero, L., Pérez, N. M., Coldwell, B. C., Pankhurst, M. J., Rodríguez, F., Asensio-Ramos, M., Padrón, E., and Hernández, P. A.: Hydrogeochemical temporal variations related to the recent volcanic eruption at Cumbre Vieja volcano, La Palma, Canary Islands, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8817, https://doi.org/10.5194/egusphere-egu22-8817, 2022.

13:26–13:32
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EGU22-8830
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Virtual presentation
José Pacheco, Alexandra Moutinho, Diogo Henriques, Marcos Martins, Pedro Hernández, Sérgio Oliveira, Tiago Matos, Dário Silva, Fátima Viveiros, José Barrancos, Diamantino Henriques, Nemesio Pèrez, Eleazar Padrón, Gladys Melián, Africa Barreto, Yenny Gonzalez, Sergio Rodríguez, Emilio Cuevas, Ramón Ramos, Paulo Fialho, Catarina Goulart, Luís Gonçalves, Carlos Faria, and João Rocha

The management of natural hazards is a vital concern for the sustainable development of any country and information is the single most important factor to tackle the risks from natural hazards within the risk reduction phase, and to manage response during a crisis. To cope with these challenges it is required, on one hand, to collect baseline information on the natural systems to understand their current state, to identify changes and predict or forecast their future behaviour and, on the other hand, to update information during crisis to review and determine management strategies.

One major difficulty to this approach is the economic weight of the classic monitoring systems, requiring heavy investments, costly maintenance, and substantial human resources. To overcome these obstacles, an alternative concept was developed based on low-cost and fast deployable wireless sensors networks made by autonomous devices, each capable to communicate to a cloud computing service that compiles and processes data, producing information readily accessible via web.

The 2021 eruption of the Cumbre Vieja volcano presented an excellent opportunity for a proof of concept of this idea. A trial run was set up on this challenging environment, focusing mainly on the detection and measurement of eruptive products, targeting the measurement of eruptive plume components, such as carbon dioxide (CO2), sulphur dioxide (SO2) and ash (particle matter, PM), and the monitoring of lava flows entering the sea. Besides the sensor’s setups, also the automatic data processing and different communications were tested.

The experiment consisted of a proximal network of different stations measuring CO2, SO2, PM10, PM2.5, temperature, and humidity; a set of trials to intercept the eruptive plume with weather balloons to measure in-situ the same parameters; a distal aethalometer to detect particles from the distal plume; and a set of buoys to monitor hydroacoustic and environmental parameters in the proximity of the lava deltas. The proximal network allowed for a continuous monitoring with information immediately available via web, with good spatial and temporal correlations between different parameters. The atmospheric soundings allowed to measure particle mass concentrations and sulphur dioxide along a profile of the eruptive plume and characterize its vertical profile, with in situ measurements, while back trajectory of air parcel analyses and aethalometer measurements carried out at Izaña Atmospheric Observatory (2367 m.a.s.l.) showed attenuation variability that could be associated with small volcanic particles transported to at least 140 km from the source. The buoys trial allowed to record the acoustic environment near the lava deltas and to test the design and configurations of the device regarding sensors integration and communications.

The Cumbre Vieja eruption experiment allowed to try-out a fast deployment low-cost multi-sensor system with good results on volcanic plume characterization and real-time data production that proved to be useful for managing volcanic crisis and demonstrated the relevance of this alternative monitoring concept.

How to cite: Pacheco, J., Moutinho, A., Henriques, D., Martins, M., Hernández, P., Oliveira, S., Matos, T., Silva, D., Viveiros, F., Barrancos, J., Henriques, D., Pèrez, N., Padrón, E., Melián, G., Barreto, A., Gonzalez, Y., Rodríguez, S., Cuevas, E., Ramos, R., Fialho, P., Goulart, C., Gonçalves, L., Faria, C., and Rocha, J.: Low-cost, fast deployment multi-sensor observations of the 2021 Cumbre Vieja eruption , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8830, https://doi.org/10.5194/egusphere-egu22-8830, 2022.

13:32–13:38
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EGU22-8873
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ECS
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Virtual presentation
Jorge Romero, Mike Burton, Francisco Cáceres, Edward Llewellin, Margherita Polacci, Maria Asensio-Ramos, Luca D'Auria, Tullio Ricci, Riccardo Civico, Jacopo Taddeucci, Daniele Andronico, Piergiorgio Scarlato, Fatima Rodríguez, Matt Pankhurst, Alba Martín-Lorenzo, and Nemesio Pérez

During September-December 2021, the Cumbre Vieja eruption (La Palma, Canary Islands) was characterised by simultaneous explosive and effusive activity (Longpré, 2021; Pankhurst et al., 2021).  The eruption produced a ~200 m high complex pyroclastic cone (Romero et al., 2022). A series of syn-eruptive lateral collapses modified the edifice morphology and caused sporadic breaching towards the west-northwest, influencing the nature and distribution of eruptive hazards.

We documented these destructive events using tremor and seismic data, as well as direct visual and thermal observations of the eruptive activity. In addition, UASs were used for aerial surveys and DEM generation in late September 2021. Field descriptions of the resulting deposits and stratigraphic sampling of tephra fallout were carried out in October and November 2021. Microanalysis of pyroclastic fragments included scanning electron microscope and electron microprobe for textural and compositional characterisation.

Two classes of collapse events were observed: the first involved a substantial portion of the cone and led to its horseshoe scar morphology; the second mainly affected ramparts of pyroclasts that separated vents along the fissure. The largest breaching event, which occurred on September 25, was generated by a high eruption rate and associated rapid deposition of pyroclasts on a steep pre-eruptive surface. Smaller collapses resulted from rapid pyroclastic agglutination on the conduit/fissure.

Some collapses triggered an immediate and substantial increase in the lava flux presumably through release of lava that has been stored in the vent and/or shallow plumbing system. The largest collapses produced lava flows up to 10 m thick which rafted decameter-sized chunks of the failed edifice. In some cases, these outpourings inundated residential areas. Collapses were sometimes followed by an increase in the eruption intensity, forming lava fountains up to several hundred metres in height; we infer these fountains resulted from unloading of the shallow plumbing system.

The 2021 eruption of Cumbre Vieja volcano provides a rare opportunity to document recurrent, syn-eruptive collapses of the vent edifice during a cone-forming eruption, and to identify and characterise the hazards associated with this common type of activity. 

References:

Longpré, M. A. (2021). Reactivation of Cumbre Vieja volcano. Science, 374(6572), 1197-1198. Doi: 10.1126/science.abm9423

Pankhurst, et al. (2022). Rapid response petrology for the opening eruptive phase of the 2021 Cumbre Vieja eruption, La Palma, Canary Islands. Volcanica, 5(1), pp. 1–10. Doi: 10.30909/vol.05.01.0110.

Romero et al. (2022). Volume and stratigraphy of the Cumbre Vieja 2021 eruption tephra fallout, La Palma Island. VMSG Virtual Annual Meeting, 10-12th January 2022, Manchester, United Kingdom.

How to cite: Romero, J., Burton, M., Cáceres, F., Llewellin, E., Polacci, M., Asensio-Ramos, M., D'Auria, L., Ricci, T., Civico, R., Taddeucci, J., Andronico, D., Scarlato, P., Rodríguez, F., Pankhurst, M., Martín-Lorenzo, A., and Pérez, N.: Syn-eruptive edifice collapses during the Cumbre Vieja (Canary Islands) 2021 eruption, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8873, https://doi.org/10.5194/egusphere-egu22-8873, 2022.

13:38–13:44
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EGU22-10749
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ECS
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Janine Birnbaum, Einat Lev, Pedro Hernandez, José Barrancos, Germán Padilla, María Asensio-Ramos, David Calvo, Fátima Rodríguez, Nemesio Pérez, and Sonia Calvari

During the main phase of the 2021 eruption of the Cumbre Vieja volcano (La Palma, Spain), eruptive activity was characterized by Strombolian eruptions, fire fountaining, white and grey ash and gas-dominated plumes, and lava effusion from multiple events. Over the period November 16 to November 26, we recorded continuous time-lapse IR images and opportunistic visible and IR videos of the vent from multiple ground-based locations. We measure the apparent area of the high-temperature gas-and-ash jet and fire fountaining from time-lapse images recorded between 1 and 60 frames/min to investigate the evolution of the explosive activity and of these plumes on minutes to days time scales. We compare plume size estimates from two different angles and vent-camera distances. We will explore periodicity and relationships between neighboring vents and discuss the implications for processes occurring in the shallow-most plumbing system of the volcano.

How to cite: Birnbaum, J., Lev, E., Hernandez, P., Barrancos, J., Padilla, G., Asensio-Ramos, M., Calvo, D., Rodríguez, F., Pérez, N., and Calvari, S.: Temporal evolution of Cumbre Vieja explosive activity and ash plumes from ground-based infrared and visible cameras, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10749, https://doi.org/10.5194/egusphere-egu22-10749, 2022.

13:44–13:50
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EGU22-9419
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Virtual presentation
Alicia Felpeto, Antonio J. Molina-Arias, Francisco Quirós, Jorge Pereda, Laura García-Cañada, and Eduardo A. Díaz-Suárez

Last year's almost 3-month eruption on the island of La Palma was a Strombolian eruption. The explosive behaviour has been very variable and significant throughout the eruption.  The IGN (Instituto Geográfico Nacional) measured the height of the eruptive column from the first days of the eruption using visual cameras. The main camera used was one from the IAC (Instituto Astrofísico de Canarias), located at 2365 masl altitude and 16.5 km north of the main vent.  The cameras were calibrated with geodetic techniques to check the accuracy of the measurements and avoid errors due to small displacements or rotation of the cameras. The effect of wind at different heights was also taken into account in the assessment of the plume height. The maximum value of the column height measured was 8500 masl, which occurred hours before the end of the eruption, while the characteristic value was about 3500 masl. This work shows the evolution of the column height throughout the eruptive period and its correlation with different volcano monitoring techniques. The measurement of the eruptive column height is of great relevance in reducing the potential impact of volcanic ash on civil aviation, as significant changes in the height of the eruptive plume are communicated to the VAAC (Volcanic Ash Advisory Centre) in Toulouse to be taken into account in volcanic ash cloud forecasts.

How to cite: Felpeto, A., Molina-Arias, A. J., Quirós, F., Pereda, J., García-Cañada, L., and Díaz-Suárez, E. A.: Measuring the height of the eruptive column during the 2021 eruption of Cumbre Vieja (La Palma Island, Canary Islands), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9419, https://doi.org/10.5194/egusphere-egu22-9419, 2022.

13:50–13:56
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EGU22-9297
Piergiorgio Scarlato, Jacopo Taddeucci, Daniele Andronico, Tullio Ricci, Riccardo Civico, Elisabetta Del Bello, Laura Spina, Luca D'Auria, Maria Asensio-Ramos, David Calvo, Eleazar Pardrón, Pedro Hernández, and Nemesio Pérez

A variety of eruptive styles concurred to define the explosive activity of the 2021 Cumbre Vieja eruption (La Palma, Canary Islands, Spain). These styles include, as broadly defined, lava fountaining, Strombolian explosions, rapid Strombolian, spattering, ash-rich jets, and ash venting, and occurred both alternately and simultaneously at the multiple vents that hosted the activity during the more-than-three-months-long eruption. In order to capture the defining features and the underlying processes of these styles and of their transitions, we deployed FAMoUS (Fast, MUltiparametric Setup) during two field campaigns, between 22 September-1 October and between 5-9 November 2021. FAMoUS includes one high-speed camera (frame rate 250 to 500 frames per second (FPS) and 0.021-0.147 m/pixel resolution at the vent), one thermal camera (up to 50 FPS and 0.2-0.8 m/pixel .ca), three high-definition cameras (25 FPS, 0.03-1.2 m/pixel ca.), and one microphone (flat response between 0.5 and 10000 Hz, sampling rate 20 kHz). Preliminary video processing results, obtained using both manual tracking and Optical Flow routines, reveal ejection velocities of pyroclasts in the 20-220 m/s range, with the highest and the lowest values of peak velocity being recorded during Strombolian explosions and ash venting, respectively. All activity styles display ejection velocity fluctuations and variably marked ejection pulses, which are more pronounced during Strombolian explosions. Lava fountains feature the highest mean ejection velocity and a variety of fluctuation patterns, with larger-amplitude and more abrupt ones when transitioning towards Strombolian explosions. The maximum settling velocity of bomb-to lapilli-sized pyroclasts in the vicinity of the vent is remarkably stable around 50 m/s. The transition between the different styles of activity is marked by changing rates of ejection pulse frequency/amplitude and relative proportions of ash and bombs, pointing to a feedback between the volume, ascent rate, and frequency of gas pockets rising in the conduit, and the changes induced by their transit through the magma residing in the uppermost termination of the conduit.

How to cite: Scarlato, P., Taddeucci, J., Andronico, D., Ricci, T., Civico, R., Del Bello, E., Spina, L., D'Auria, L., Asensio-Ramos, M., Calvo, D., Pardrón, E., Hernández, P., and Pérez, N.: Styles of explosive activity during the 2021 Cumbra Vieja eruption, as illuminated by high-frequency imaging and acoustic sensing, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9297, https://doi.org/10.5194/egusphere-egu22-9297, 2022.

13:56–14:02
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EGU22-5041
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Highlight
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Virtual presentation
Thomas R. Walter, Edgar Zorn, Pablo J. Gonzalez, Simon Plank, Valeria Munoz Villacreses, Alina Shevchenko, Nicole Richter, and Carla Valenzuela Malebran

Volcanic terrains host complex and commonly steep morphologies and are often also subject to tensile and shear faulting episodes. Previous studies demonstrated that strike slip and dip slip faults deflect at topographic highs and may locally diverge to develop multiple fault branches with varying strike and dip directions. Although fault deflection is associated with dike-related faults, a direct link to the positioning of eruption craters could not be established yet. Here we show that the Cumbre Vieja eruptions occurred in a complex pre-existing topographic and structural environment that affected fault development and evolution of eruption vents. 

We investigate available satellite radar data from the CosmoSkymed and TerraSAR-X missions, to track the temporal and spatial evolution of summit craters and faults. We find that summit craters are closely aligned in a direction NW-SE and developing a nested structure. We also conducted repeat drone measurements to acquire close-range optical images of the summit and nearby flanks. Results allow an in-depth analysis of the morphology of craters and the geometry, traces and throws of faults. We find that in late stages of the eruption important tensile faults evolve, and deflect at pre-existing topographic highs. We further find that these faults are developing complex sinkholes and secondary features due to their burial by loose unconsolidated material (i.e. tephra), and that the faults converge again at topographic lows, with varying degrees of the slip or dilation tendency. We discuss the coalignment of these structures with crater alignments, and present results from analogue models aiming to better constrain the varying deflection of faults controlled by topography.

How to cite: Walter, T. R., Zorn, E., Gonzalez, P. J., Plank, S., Villacreses, V. M., Shevchenko, A., Richter, N., and Malebran, C. V.: Faulting and crater development controlled by pre-existing topography - evidence from drone and satellite observations during the 2021 Cumbre Vieja eruption, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5041, https://doi.org/10.5194/egusphere-egu22-5041, 2022.

14:02–14:08
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EGU22-11927
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Highlight
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Virtual presentation
Costanza Bonadonna, Marco Pistolesi, Marija Voloschina, Maria-Paz Reyes Hardy, Lucia Dominguez, Alba Martin, Jorge Eduardo Romero Moyano, Camille Pastore, Daniele Andronico, Corrado Cimarelli, Beverley Coldwell, Ulrich Kueppers, Fátima Rodríguez, Matt Pankhurst, Margherita Polacci, Piergiorgio Scarlato, and Jacopo Taddeucci

Between 19 September and 13 December 2021 (85 days), a flank eruption took place along the Cumbre Vieja ridge (La Palma Island), one of the most active volcanic centers of Canary Islands. The last 7000 years of Cumbre Vieja activity has been characterized by a combination of effusive and explosive eruptions. These generated both cinder cones and lava flows. The previous event occurred between October 26 and November 28, 1971 (eruption of Teneguía). The 2021 eruption was characterized by the alternate (and often simultaneous) emission of lava flows, lava fountains and tephra plumes along a ~1 km-length fissure consisting of about ten vents that built a cinder cone complex. The southern vents were mostly associated with the generation of tephra plumes and lava fountains, while the northern vents were mostly associated with the generation of lava flows. The ~12 km2 lava flow field on the west side of the island reached the sea on September 28, forming a new lava delta and interacting with sea water producing lava haze (i.e. laze). Even though tephra was sedimented all over La Palma and sometimes reached the neighboring islands, the cumulative tephra deposit is mostly elongated towards the southwest and the northeast due to the prevailing wind direction, reaching a maximum thickness southwest of the fissure. Both lava fountains and more explosive tephra plumes contributed to the formation of the tephra deposit. Tephra plumes were associated with variable intensity reaching a few kilometers of altitude (<10 km). Multiple tephra layers, which are associated with distinct phases of the eruption, can be identified based on grainsize, clast texture and deposit characteristics. Some of the layers are dominated by black fluidal glassy clasts mostly associated with lava fountain activity, while some others are dominated by brown, finely to coarsely vesicular clasts mostly associated with more explosive tephra plumes. Most layers, as well as the cumulative deposit, are characterized by a thinning break-in-slope between 3-4 km from the vents. A distinctive lithic-rich, reddish layer, which mostly sedimented on October 15-16 during a new vent opening phase, helps the correlation among the various layers. Grainsize on land is dominated by lapilli and coarse ash, with fine ash being mostly deposited in the ocean (beyond 6 km from the vents). Individual layers are associated with volumes that range between Volcanic Explosivity Index (VEI) 2 and 3, while the total tephra deposit is associated with a VEI 3 (excluding the volume of the cone).

How to cite: Bonadonna, C., Pistolesi, M., Voloschina, M., Reyes Hardy, M.-P., Dominguez, L., Martin, A., Romero Moyano, J. E., Pastore, C., Andronico, D., Cimarelli, C., Coldwell, B., Kueppers, U., Rodríguez, F., Pankhurst, M., Polacci, M., Scarlato, P., and Taddeucci, J.: Characterization of the tephra deposit associated with the 2021 eruption of Cumbre Vieja (La Palma), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11927, https://doi.org/10.5194/egusphere-egu22-11927, 2022.

14:08–14:14
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EGU22-9986
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ECS
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On-site presentation
Alba Martín Lorenzo, Daniele Andronico, Fátima Rodríguez, Beverley Coldwell, Matt Pankhurst, Jacopo Taddeucci, Piergiorgio Scarlato, Costanza Bonadonna, Marco Pistolesi, Jorge E. Romero, Gladys Melián, and Nemesio M. Pérez

On September 19, 2021, the Cumbre Vieja volcano (La Palma, Canary Islands) erupted after 50 years dormant; the last eruption occurred in 1971, forming the Teneguía cone. Historical volcanism on La Palma typically produces simultaneous explosive/effusive eruptions producing cinder cones, tephra deposits and lava flow fields. The 2021 eruption was characterized by almost continuous tephra emission along a ~ 1 km long fissure, with only a few phases of quiescence lasting no more than few hours. Up to ten explosive vents were active at different times, with eruptive styles ranging from ash-venting, powerful Strombolian activity and lava fountaining. These formed volcanic plumes occasionally reaching 6-7 km above the growing composite cone. Coeval lava flows with variable, but mostly high effusion rates accompanied the explosive activity. The eruption stopped after 85 days on December 13, 2021.

Studying the textures and morphology of tephra deposits can help define and classify the explosive processes that dominated the rise of magma and its fragmentation. For this reason, from the onset of the eruption, tephra samples were collected daily. These samples represent airfall from the plume, and were collected at distances between 1 and 13 km from the new Cumbre Vieja cone. Samples were used to evaluate the mass load per square meter unit, together with grain-size analysis. During the study period, 87 samples were weighed, giving tephra mass loads between 0.10 kg/m2 and 79 kg/m2. These values can be used for estimating the total erupted tephra mass within the first period of the eruption. The grain-size distribution of samples was measured at half-phi steps by CAMSIZER (Retsch), and shows significant temporal variation in magma fragmentation and dispersal. This can be correlated to variations in plume height and eruption style.

Componentry analysis on ash samples was performed to assess both style and changes in the explosive activity. Seventeen ash samples (22 September – 1 November) were sieved to separate the 0.25-0.5 mm fraction, which allows easier distinction of particle components. Four types of components were recognized: sideromelane, tachylite, lithics and free crystals, each one characterized by different morphological and textural features. During the opening phase, a high percentage of sideromelane was erupted, then over the following weeks an increase in both lithic particles and variations in morphological features of sideromelane fragments were observed. Fragmentation-related broken crystals within intact particles are also found.

These preliminary results match the variability in eruption styles observed. They confirm that tephra studies may constitute a powerful tool for monitoring ongoing intense eruptions by helping to comprehend, together with other techniques, the evolution of eruption dynamics, magma processes, and magma level in volcanic conduits.

How to cite: Martín Lorenzo, A., Andronico, D., Rodríguez, F., Coldwell, B., Pankhurst, M., Taddeucci, J., Scarlato, P., Bonadonna, C., Pistolesi, M., Romero, J. E., Melián, G., and Pérez, N. M.: Preliminary results from textural studies on tephra deposits erupted during the 2021 eruption at Cumbre Vieja volcano, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9986, https://doi.org/10.5194/egusphere-egu22-9986, 2022.

14:14–14:20
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EGU22-11700
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ECS
Fabrizio Di Fiore, Alessandro Vona, Alex Scarani, Guido Giordano, Claudia Romano, Daniele Giordano, Luca Caricchi, Alba Martin-Lorenzo, Fatima Rodriguez, Beverley Coldwell, Pedro Hernandez, and Matt Pankhurst

After half a century of quiescence, activity at Cumbre Vieja volcano (La Palma, Canary Islands, Spain) restarted with a spectacular flank eruption characterized by both high fire fountaining and effusive activity. The products emitted comprise tephra fall and lava flows, ranging from tephrite to basanite. Between September 19th and December 13th 2021 the lava flows covered ~ 12,5 km2, affecting more than 3000 buildings and paralyzing the viability and the essential activity on the SW sector of the island. This scenario highlights the importance of rheological data deriving from experimental studies of such low viscosity magma to better understand lava flow emplacement dynamics, hazard and mitigate risk.

We performed a detailed experimental study to characterize the rheology of the basanitic lava sampled between October 3rd and 7th in a Concentric Cylinder set-up. Starting from a superliquidus state of 1400 °C, a set of isothermal deformation experiments was carried out at different target subliquidus temperatures (from 1225 to 1175 °C) and fixed shear-rate of 10 s-1 to investigate the near equilibrium viscosity. Moreover, a series of cooling deformation experiments were performed at different cooling-rates (ranging from 0.1 to 10 °C/min) and at constant shear-rate of 10 s-1 with the aim to mimic the dynamic evolution of natural flowing lava through controlled cooling-rate conditions. In isothermal deformation experiments, the steady state conditions (i.e., stable crystal contents) were achieved faster at increasing degree of undercooling, showing a progressive increase in the final viscosity values. In cooling deformation experiments, with increasing cooling-rate applied, the onset of crystallization took place at progressively lower temperature over shorter timescales. The experiments performed at cooling-rates from 0.1 to 1 °C/min were interrupted when viscous rupture (i.e., the transition from coherent flow to shear localization and physical separation) was observed. For the experiments conducted at higher cooling-rates (i.e., from 3 to 10 °C/min), the experimental runs were stopped at viscosity values of ~104 (Pa s), when the stress limit of the device was achieved.

Preliminary results show that the thermal history plays a fundamental role on the kinetics of the crystallization hence modulating the capacity of lava to flow. The different viscosity paths observed at low and high cooling-rates lead to a rheological decoupling between the slow-cooling core and the fast-cooling external part of the lava flows. This process would be key in promoting the transition from pahoehoe to ‘a‘ā emplacement regimes, ultimately controlling the runout distance of lava flows.

How to cite: Di Fiore, F., Vona, A., Scarani, A., Giordano, G., Romano, C., Giordano, D., Caricchi, L., Martin-Lorenzo, A., Rodriguez, F., Coldwell, B., Hernandez, P., and Pankhurst, M.: Preliminary results on the rheological characterization of the 2021 lava from Cumbre Vieja volcano (La Palma, Canary Islands, Spain), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11700, https://doi.org/10.5194/egusphere-egu22-11700, 2022.

14:20–14:26
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EGU22-10531
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Highlight
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Virtual presentation
Einat Lev, Janine Birnbaum, Pedro Hernandez, José Barrancos, Samantha Tramontano, Laura Connor, Charles Connor, and Jose Gabriel

Over the three-month duration of the 2021 Cumbre Vieja eruption, lava flows covered an area of 1,241 ha. (12.41 km2) out of the total 8,790 ha (87.90 km2) impacted by the eruption overall. Consequently, lava is responsible for the destruction of a majority of the 3,000 buildings and large agricultural areas. At the beginning of the eruption, authorities used a model to forecast the inundation areas. We compare that preliminary forecast with those produced by other models, such as MOLASSES, Q-LAVHA, MrLavaLoba, VolcFlow, and others. The different forecasted flow fields are also compared with the evolution of the flow field as observed by satellite and aerial mapping. Where available, we anchor dynamic model predictions for observables such as flow velocity to local measurements obtained from velocimetry on UAV and ground-based videos of flowing lava. Lava properties used in the models are informed by petrological analysis of samples collected during the eruption. 

How to cite: Lev, E., Birnbaum, J., Hernandez, P., Barrancos, J., Tramontano, S., Connor, L., Connor, C., and Gabriel, J.: Lava flow dynamics during the 2021 Cumbre Vieja eruption, La Palma, Spain, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10531, https://doi.org/10.5194/egusphere-egu22-10531, 2022.

Petrology
14:26–14:32
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EGU22-9661
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On-site presentation
Katy J Chamberlain, Jane H Scarrow, Matthew J Pankhurst, Olivia A Barbee, David A Neave, Dan J Morgan, Penny Wieser, Beverley C Coldwell, James Hickey, Alba Martín-Lorenzo, Fátima Rodríguez, Gavyn K Rollinson, William Hernández, Pedro A Hernández, and Nemesio M Pérez

On 19 September 2021, Cumbre Vieja volcano, La Palma, Canary Islands erupted after 50 years of quiescence. The eruption lasted 85 days, ending on 13 December. At present, whilst geophysical data may be used to estimate the scale of magma reservoirs (and when combined with the magma output rate can provide a guide to eruption longevity), experience shows that using such techniques to see through activity at crustal levels and quantify deeper magmatic processes during an eruption is not always productive or possible. Success of geophysical techniques is dependent on both the level of instrumentation and the degree to which local magmatic and tectonic environments are understood. Thus, deep magma supply and crustal interactions may be intractable or even invisible, even if they are seismogenic. Simple on-site compositional information (e.g. from handheld XRF) can indicate broad-scale changes in erupted compositions and reflect, for example,  changes in crystallinity or melt composition. However, such bulk data can be ambiguous and therefore insufficiently robust to be useful for decision-makers. In contrast, petrological observations of mineral textures and compositions can provide direct, quantifiable evidence of deep and shallow magmatic processes that, in tandem with upper crustal stress states, ultimately drive magma ascent and eruption. Advancements in the use of precise and automated sample preparation techniques, rapid and high-resolution textural and compositional characterisation, and increasing computing capacity now allows samples to be collected, analysed and interpreted within days rather than months. Measurements of volcanic products include: textures, mineralogy, mineral chemistry (and profiles), whole-rock geochemistry, volatiles, isotope geochemistry and rheology. Petrology combines these data into interpretations of the magmatic system state and evolution, which can inform understanding of the dynamic processes driving eruptions and physical behaviours of tephra and lava. Hence, forecasts of volcanic behaviour underpinned by petrological characterization and trends are more robust. Here we present textural and chemical data from time-resolved samples of lavas and tephras from the eruptive sequence, marking the initiation, duration and cessation of volcanism. These data are used to constrain and trace temperature(s) and pressure(s) of mineral growth and magma storage; mineral-melt equilibrium dynamics; and timescales of magmatic processes through diffusion chronometry. Initial petrographic study has shown the lavas to be hypocrystalline, porphyritic and vesicular. Clinopyroxene is the most common coarse mineral, with olivine and amphibole also present; however, these mineral abundances are not constant through time. This study highlights the importance of time-resolved sampling and shows how both rapid qualitative observations and in situ petrological characterisation can be used to couple volcanic behaviour with subsurface magma dynamics.

How to cite: Chamberlain, K. J., Scarrow, J. H., Pankhurst, M. J., Barbee, O. A., Neave, D. A., Morgan, D. J., Wieser, P., Coldwell, B. C., Hickey, J., Martín-Lorenzo, A., Rodríguez, F., Rollinson, G. K., Hernández, W., Hernández, P. A., and Pérez, N. M.: Time series petrological insights into magmatic evolution during the 2021 Cumbre Vieja eruption, La Palma, Canary Islands, Spain, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9661, https://doi.org/10.5194/egusphere-egu22-9661, 2022.

14:32–14:38
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EGU22-6419
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ECS
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Virtual presentation
Oliver Higgins, Corin Jorgenson, Alessandro Musu, Fátima Rodríguez, Beverley Coldwell, Alba Martín-Lorenzo, Matt Pankhurst, Luca D’Auria, Guido Giordano, and Luca Caricchi

Magma has a dynamic and often-complex journey from source to surface, the record of which is largely encoded in the chemistry of minerals. Its storage conditions prior to eruption and modifications during ascent can influence eruptive dynamics and eruption duration. We present quantitative 2D chemical maps of clinopyroxene crystals from the Cumbre Vieja eruption (La Palma, Canary Islands; 19th September 2021 – 13th December 2021). The histories of individual crystals are constrained using novel thermobarometric (pressure, temperature) and chemometric (equilibrium melt composition) machine learning algorithms. We identify the remobilisation of colder (~950 ˚C), deeper (2 – 3.5 kbar), and more evolved (1 – 2 wt% MgO) cores by a hotter (1050 – 1100 ˚C) and less-evolved (3.5 – 4.5 wt% MgO) carrier melt. Textural evidence shows resorption of these antecrystic cores suggesting an uninterrupted ascent through the crustal column followed by upper-crustal (~ 1kbar) crystallisation and eruption. By using both quantitative maps and reliable single-phase thermobarometric and chemometric calibrations, we overcome several issues associated with acquiring statistically representative mineral chemistry via single spot analyses. In doing so we precisely track the syn-eruptive evolution of storage pressure-temperature and magma composition. These parameters are then related to the variation of geophysical signals (seismicity, gas monitoring) recorded during the La Palma eruption.

How to cite: Higgins, O., Jorgenson, C., Musu, A., Rodríguez, F., Coldwell, B., Martín-Lorenzo, A., Pankhurst, M., D’Auria, L., Giordano, G., and Caricchi, L.: Texturally constrained machine learning thermobarometry and chemometry of the Cumbre Vieja 2021 eruption, La Palma, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6419, https://doi.org/10.5194/egusphere-egu22-6419, 2022.

14:38–14:44
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EGU22-10124
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Virtual presentation
Marc-Antoine Longpré, Samantha Tramontano, Franco Cortese, Fátima Rodríguez, Beverley Coldwell, Alba Martín-Lorenzo, Olivia Barbee, Matthew Pankhurst, and Andreas Klügel

The 2021 eruption of Cumbre Vieja volcano (La Palma, Canary Islands) produced sustained Strombolian to violent Strombolian explosive activity, resulting in widespread tephra fall deposits in addition to lava flows. Frequent sampling of rapidly quenched volcanic ash provides the rare opportunity to document the compositional evolution of fragmenting magma at a high temporal resolution. Here we present preliminary textural observations and electron microprobe measurements of matrix glass from dated ash samples spanning the first four weeks of the eruption. Ash shards show two broad types of groundmass texture: Type 1 groundmass comprises abundant glass with microlites of plagioclase, clinopyroxene, and Fe-Ti oxides ± olivine, whereas Type 2 groundmass is microcrystalline (plagioclase, clinopyroxene, Fe-Ti oxides) and contains little to no glass. Type 1 and Type 2 groundmasses are sometimes observed mingling together at the ash shard scale. The glass composition of Type 1 groundmass is consistently tephritic, but displays significant variations over time. Glass from the earliest sample collected on 19 September is among the most primitive of the sequence, with 46.4 wt.% SiO2 and 4.0 wt.% MgO. In contrast, a sample erupted on 21–22 September records a shift to higher silica content (48.2 wt.%) and lower MgO (3.6 wt.%). Over the following five days (until 27 September), glasses return to lower silica contents, down to 45.9 wt.%, and then continue to evolve more subtly towards more primitive compositions for the next three weeks. Overall, from 21 September to 16 October, SiO2 decreases from 48.2 to 45.1 wt.%, while FeOt and MgO increase from 9.6 to 11.8 wt.% and from 3.6 to 4.1 wt.%, respectively. Chlorine concentrations also decrease from 1300 to 830 ppm. We interpret Type 1 groundmass to represent the main magma batch feeding the 2021 eruption. The observed temporal trends may be related to variable extents of microlite crystallization, particularly Fe-Ti oxides, as suggested by the association of high SiO2, low FeOt and high Fe-Ti oxide crystal fractions for the 21–27 September samples. We note that these samples coincide with a phase of the eruption characterized by highest volcanic tremor amplitudes and lowest eruption column heights (≤3 km). The origin of microcrystalline Type 2 groundmass is more ambiguous, but it may represent Type 1 magma that has undergone a more protracted cooling history, a remobilized mushy magma intersected by Type 1 magma, or lithic material. Further textural and chemical analyses of Type 1 and Type 2 groundmasses are underway to tell these scenarios apart.

How to cite: Longpré, M.-A., Tramontano, S., Cortese, F., Rodríguez, F., Coldwell, B., Martín-Lorenzo, A., Barbee, O., Pankhurst, M., and Klügel, A.: Temporal evolution of melt composition during the 2021 Cumbre Vieja eruption, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10124, https://doi.org/10.5194/egusphere-egu22-10124, 2022.

14:44–14:50
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EGU22-12452
Theodoros Ntaflos, Federico Casetta, Andrès Sandoval-Velasquez, Andrea Luca Rizzo, Alessandro Aiuppa, Mar Alonso, Eleazar Padron, Matthew Pankhurst, and Nemesio Perez

Small, cm-sized ultramafic xenoliths have been reported from the opening phase of the 2021 eruption at Cumbre Vieja, where clinopyroxene aggregates, sometimes amphibole, olivine and/or magnetite-bearing (Pankhurst et al., 2021), likely represent early fractionation products and/or relics of mush-like systems located beneath the volcanic edifice.

Detailed sampling of the lavas produced during the intermediate-late eruptive phase (November 9th) revealed the existence, in the massive portion of the flows, of a 1 cm sized dunitic xenolith with protogranular to partly recrystallized texture. The internal portion of the xenolith is composed of Fo88-89 olivine (0.33-0.34 wt% NiO), Ti-Al-poor clinopyroxene (Mg# = 87-92; Al2O3 <1.7 wt%; TiO2 <0.5 wt%), Cr-rich spinel and rare Mg-rich orthopyroxene (Mg# = 88-91; Al2O3 from 0.4-0.5 to 1.7-1.9 wt%). Textural and chemical data (Fe-Mg distribution) indicate that olivine, orthopyroxene and clinopyroxene are not far from equilibrium. Preliminary calculations show that the equilibrium T recorded by the xenolith ranges from 950 to 1070°C, with good consistency between results obtained from olivine-spinel and orthopyroxene-clinopyroxene pairs. Silica oversaturated interstitial glasses (SiO2= 67 wt%) were found in the partly recrystallized part of the xenolith.

Part of the coarse-grained xenolith forms a corona of fine-grained and worm-like association of, olivine, orthopyroxene, clinopyroxene and spinel. Both parts are surrounded by a continuous narrow external zone consisting of Ti-magnetite and sub-euhedral greenish Ti-augite, which is in contact with the host basalt. The composition of olivine and orthopyroxene in the corona keeps getting more Fe-rich towards the external zone whereas the clinopyroxene changes gradually from Ti-free to Ti-bearing diopside.

The small xenolith recovered from the November 9th lava flow is apparently a mantle-derived xenolith similar to those from the Duraznero 1949 eruption described by Klügel (1998), and those from the San Antonio 1677 eruption described by Neumann & Wulff-Pedersen, 1997.  On the way to surface, the mantle xenolith likely reacted with basaltic melts to form the first corona. These processes presumably took place in depths between 0.10-0.12 GPa as can be inferred by the presence of silica oversaturated glasses (Neumann & Wulff-Pedersen, 1997). The external zone probably formed as the result of a late-stage stagnation of the host magma at sub-crustal depths, as suggested by the compositional similarity between the clinopyroxene-spinel assemblage and the phenocrysts in the matrix.

               

Klüger, A. (1998). Reactions between mantle xenoliths and host magma beneath La Palma (Canary Islands: constraints on magma ascent rates and crustal reservoirs. Contrib Mineral Petrol 131:238-257

Neumann, E.-R. and E. Wulff-Pedersen (1997). The Origin of Highly Silicic Glass in Mantle Xenoliths from the Canary Island. Journal of Petrology 32: 1515-1539

Pankhurst, M. J., et al., (2021). Petrology of the opening eruptive phase of the 2021 Cumbre Vieja eruption, La Palma, Canary Islands. Volcanica: 5(1), 1–10

How to cite: Ntaflos, T., Casetta, F., Sandoval-Velasquez, A., Rizzo, A. L., Aiuppa, A., Alonso, M., Padron, E., Pankhurst, M., and Perez, N.: Mantle-derived xenoliths from the Cumbre Vieja 2021 lava flows: insights on the composition of the lithosphere beneath La Palma (Canary Islands), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12452, https://doi.org/10.5194/egusphere-egu22-12452, 2022.

Coffee break
Chairpersons: Carmen López Moreno, Luca D&#39;Auria
15:10–15:16
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EGU22-9557
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Highlight
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Virtual presentation
Jane H. Scarrow, Katy J. Chamberlain, Matthew J. Pankhurst, Olivia A. Barbee, Beverley C. Coldwell, James Hickey, David A. Neave, Daniel J. Morgan, Alba Martín-Lorenzo, Fátima Rodríguez, Gavyn K. Rollinson, William Hernández, Pedro A. Hernández, and Nemesio M. Pérez

On 19 September 2021, Cumbre Vieja volcano, La Palma, Canary Islands erupted after 50 years of quiescence. The eruption lasted 85 days through to 13 December. Cone building that initiated from the main fissure vent resolved into discrete emission centres dominated by ash plumes and lava fountains that fed flows that coursed to the west and west-southwest. The lava flow field covers over 1000 hectares and is up to 3.5 km wide and ~6.2 km long. Tephra fall covers over 5,500 hectares with volcanic plume heights reaching up to 6000 m depositing material mainly in the eastern part of the island but, on occasion, reaching other Canary islands: El Hierro, La Gomera, Tenerife and Gran Canaria.

Significantly, uncertainties exist regarding how such eruptions initiate, evolve and ultimately cease, e.g. changes in magma composition and volume. Here we show time series whole-rock and mineral chemistry variations throughout the eruption from initiation to paroxysm and finally cessation. Bulk chemical trends of erupted products in the first week together with textural and mineralogical observations made within a few weeks of samples’ eruption provide an initial benchmark for understanding the evolution of the eruption. Petrographically, the lavas are hypocrystalline, porphyritic and vesicular. Clinopyroxene is the most common coarse mineral with olivine and amphibole also present. Whole-rock XRF and ICP-MS analyses show that samples have restricted, primitive, metaluminous, alkaline whole-rock compositions; geochemically, lavas plot as basanite-tephrites, but mineralogical observations, for example the absence of feldspathoids, classify them as alkali basalts.

Time-resolved whole-rock analyses through the eruption show increasing MgO contents and decreasing incompatible element contents, which may reflect changes in melting dynamics or crystal cargos. A jump in whole-rock major and trace element compositions on day 7 to 8 of the eruption coincides with the disappearance of resorbed amphibole crystals in the thin sections, and also the amphibole peak in XRD spectra, as well as transition to the eruption of less viscous lava flows. The whole-rock compositional changes also correlate with variations in geophysical monitoring records of real-time seismic amplitude measurements.

Our new data has potential to be applied to eruption forecasting, as well as evaluation of volcanic hazards and associated risks for activity in the Canary Islands and other comparable ocean island systems.

How to cite: Scarrow, J. H., Chamberlain, K. J., Pankhurst, M. J., Barbee, O. A., Coldwell, B. C., Hickey, J., Neave, D. A., Morgan, D. J., Martín-Lorenzo, A., Rodríguez, F., Rollinson, G. K., Hernández, W., Hernández, P. A., and Pérez, N. M.: Time series compositional insights into magmatic evolution during the 2021 Cumbre Vieja eruption, La Palma, Canary Islands, Spain, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9557, https://doi.org/10.5194/egusphere-egu22-9557, 2022.

15:16–15:22
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EGU22-10914
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ECS
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Virtual presentation
Samantha Tramontano, Marc-Antoine Longpré, Franco Cortese, Fátima Rodríguez, Beverley Coldwell, Alba Martín-Lorenzo, Olivia Barbee, and Matthew Pankhurst

Cumbre Vieja volcano, on La Palma, Canary Islands, Spain, is an excellent natural laboratory for exploring igneous processes at the individual eruption scale (e.g. eruption precursors) and at the larger volcanic-magmatic-system scale (e.g. repose period) because of similar eruptive styles, volumes, and chemical compositions across historical eruptions [1]. To determine the timing and nature of perturbations during pre-eruptive magma assembly and how they may relate to variations in eruption repose and style, we analyze and model the chemical fingerprints of tephra glass and tephra-hosted crystals at the system scale (sampling of all eruptions since 1585) and at the eruption scale (daily sampling of the 2021 eruption). Broadly, the tephra-olivine record is remarkably similar across samples from the 2021, 1971, 1949, 1712, 1677, 1646, and 1585 eruptions: 86% of analyzed crystals (n=85) display a more evolved core composition (Fo80 ± 1.4), followed by a reversely zoned inner rim (Fo82 ± 0.9) and a steeply, normally zoned outer rim (as low as Fo73). Reversely and normally zoned crystal segments respectively show convex and concave Fo–Ni relationships, correspondingly indicating diffusion- and growth-dominated zoning mechanisms. At a finer temporal scale, we observe systematic chemical variability over the first four weeks of the 2021 eruption. At least three distinct chemical flavors can be distinguished thus far: 1) 19-Sept products are most primitive (tephra glass is 46.4 ± 0.3 wt.% SiO2, containing olivine up to Fo87), 2) 22-Sept products are most evolved (tephra glass is 48.2 ± 0.7 wt.% SiO2, containing Fo79 ± 0.8 olivine), and 3) products from 22-Sept to 15-Oct become more primitive over time (tephra glass averages 45.9 ± 0.5 wt.% SiO2 and contains Fo82 ± 1.0 olivine).  Based on these zoning patterns and the application of diffusion chronometry to reverse zones, we propose that episodic injections of primitive melt from depth invade more evolved crystal mushes days to months before and during eruption. Fo-Ni relationships along olivine traverses and thermodynamic decompression models suggest that these crystals are then entrained in an ascending and evolving carrier liquid, crystallizing normally zoned overgrowth rims before eruption.  Our work suggests that primitive melt recharge is a critical mechanism for reactivating and sustaining activity at Cumbre Vieja, and we find that the timings of primitive injections (or recharge events) are not related to repose periods between eruptions. Rather, we propose that it is the timing and volume of primitive melt generation and extraction in the upper mantle that strongly influences volcano reactivation and may influence eruption style and duration.

[1] Longpré and Felpeto (2021), JVGR

How to cite: Tramontano, S., Longpré, M.-A., Cortese, F., Rodríguez, F., Coldwell, B., Martín-Lorenzo, A., Barbee, O., and Pankhurst, M.: Reactivation of Cumbre Vieja volcano: Insights from a paired tephra glass and olivine crystal record, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10914, https://doi.org/10.5194/egusphere-egu22-10914, 2022.

15:22–15:28
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EGU22-10203
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Virtual presentation
Vittorio Zanon, Klaudia Cyrzan, Luca D'Auria, Matt Pankhurst, Fátima Rodríguez, Beverley Coldwell, and Alba Martín-Lorenzo

The recent eruption from the Cumbre Vieja volcanic system at La Palma Island (19 September to 14 December 2021) occurred through the impulsive emission of various batches of magma. The first emitted magma is a tephrite (clinopyroxene, amphibole and rare olivine phenocrysts). The following pulses erupted basanites (clinopyroxene and olivine phenocrysts).

Fluid inclusions and seismicity data of the first 40 days of activity are here merged to provide a snapshot of the magma ascent path.

Fluid inclusions form trails through the crystals or are more rarely in isolated clusters. They show evidence of partial density re-equilibration events. At room temperature are single phase (L) or may contain a vapour bubble (V+L).

Trapped fluid is pure CO2 (Tm=-56.6 ±0.1 °C). Final inclusion homogenisation occurred to the liquid (ThL) phase in all crystals and to the vapor (Thv) in few olivines. The corresponding density values have been recalculated to account for max 10% water in the trapped fluid.

In amphiboles (N=60) ThL=23.3-30.9 °C (ρr=546-768 kg·m3);

In clinopyroxenes (N=69) ThL=27.2-31 °C (ρr=514-703 kg·m3);

In early olivines (N=241) ThV=30.4-30.9 °C (ρr=382-464kg·m3); ThL=-6.2-31 °C (ρr=492-963 kg·m3);

In late october olivines (N=180) ThV=30.9 °C (ρr=464kg·m3); ThL=20.6-30.9 °C (ρr=546-802 kg·m3).

The histograms of density data reveals fluid trapping and re-equilibration events. Pressures were obtained from isochore distribution in the P-T space at the trapping temperature of 1075 °C for the tephrite and 1150° C for the basanite.

The tephrite ascended from a depth of ~17.2 km (487 MPa) and partially re-equilibrated at ~14.2 km (392 MPa), ~11.5 km (307 MPa), ~10 km (264 MPa) and ~8.2 km (218 MPa).

Basanites ascended from (or through) a depth between ~25.8 and ~22.6 km (656-757 MPa). Multiple ponding stages are between ~19 and ~17 km deep (484-543 MPa), at ~12 km (336 MPa) and from ~8.7 to ~6.1 km (162-229 MPa).

This picture agrees with the spatial and temporal pattern of the seismicity recorded during the eruption. After a very rapid pre-eruptive phase, lasting about a week, in which hypocentres rapidly ascended from about 10 km depth up to the surface a few hours before the eruption, seismicity waned considerably in just a few days. Since 27 September, a progressive increase of the seismicity in a cluster located at about 8-12 km depth was observed. In the following days, we observed the appearance of another cluster of hypocentres at a depth of about 20-25 km. Seismicity increased progressively during the first weeks of October, with many events having magnitudes higher than 4 in both clusters. The seismicity started waning at the beginning of December, disappearing almost entirely at the end of the eruption. We interpret these syn-eruptive seismicity clusters at the effect of crustal readjustment following the rapid emptying of two magmatic reservoirs located respectively just beneath each seismicity cluster. This model agrees well with the bimodal depth range inferred from fluid inclusion, as well as with the observed variation in the composition during the eruption.

How to cite: Zanon, V., Cyrzan, K., D'Auria, L., Pankhurst, M., Rodríguez, F., Coldwell, B., and Martín-Lorenzo, A.: The magma ascent path during the 2021 eruption of Cumbre Vieja (La Palma Island, Canary archipelago) highlighted by fluid inclusions and seismicity, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10203, https://doi.org/10.5194/egusphere-egu22-10203, 2022.

Environment
15:28–15:34
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EGU22-9754
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On-site presentation
Beverley Coldwell, David Wertheim, Lisa Miyashita, Richard Giddens, Ian Gill, Jonathon Grigg, and Nick Petford

While studies have shown adverse health effects associated with volcanic eruptions are thought to result from resultant gases and ash particle clouds, the precise reasons remain unclear. However, the shape of particles has previously been shown to influence their ability to adhere to human cancer cells (He and Park 2016). Furthermore grain size and the presence of silica are thought to be important in understanding respiratory effects associated with volcanic ash particles.

We have previously shown that volcanic ash particles can have sharp appearing surface features from 3D confocal microscopy (Wertheim et al. 2017). The aim of this study was to examine the 3D appearance, chemistry and adherence to cells of volcanic ash particles from the September 2021 La Palma eruption in particles of size PM10 as they are considered of particular interest in respiratory conditions. Volcanic ash particles collected from the first day of the eruption were imaged using confocal scanning laser microscopy and scanning electron microscopy in order to assess their 3D appearance and geometry. In addition, 2D shape and elemental analysis, obtained from secondary and backscattered electron imaging, was performed to link ash particle geometry with composition.

Initial results confirming the angular (3D-fragmented) nature of PM10 and smaller particles from the La Palma eruption, suggest an ability to adhere to cells. Experiments to confirm this by exposing A549 human adenocarcinomic epithelial cells to La Palma ash particles are ongoing.

How to cite: Coldwell, B., Wertheim, D., Miyashita, L., Giddens, R., Gill, I., Grigg, J., and Petford, N.: La Palma PM10 ash particle geometry and adherence to pulmonary cell tissue, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9754, https://doi.org/10.5194/egusphere-egu22-9754, 2022.

15:34–15:40
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EGU22-7705
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On-site presentation
Pedro A. Hernández, Eleazar Padrón, Gladys V. Melián, Nemesio M. Pérez, Germán Padilla, María Asensio-Ramos, Daniel Di Nardo, José Barrancos, José M. Pacheco, and Maud Smit

The recent volcanic eruption of Cumbre Vieja, on the island of La Palma, has beenconsidered by many to be the most important and devastating urban eruption of the last 100 years in Europe. After its completion on December 13, 2021, some urban areas not directed damaged by lava flows are affected by strong carbon dioxide (CO2) emissions from the soil. CO2 is a toxic gas at high concentration, as well as an asphyxiant gas and may be lethal when present in concentrations higher than 15 V%. The base of the small cliff where the La Bombilla neighborhood is located as well as the basements and garages of numerous buildings in the town of Puerto Naos, seem to represent leaking pathways along which CO2 related to the volcanic-hydrothermal activity rises to the surface. In order to assess the hazard represented by the endogenous gas emissions, a scientific observational study was undertaken by means of diffuse CO2 and H2S efflux measurements as well as gas sampling from the soil atmosphere at 40cm depth and the measurement of the soil temperature at 15cm and 40cm in 97 points homogeneous distributed at La Bombilla and Puerto Naos, in order to delimit anomalous gas emission zones and to know the emission rates of the measured gases. Also we carried out the installation of a Tunable Diode Laser system to measure continuously the CO2 air concentrations in the basement of a building at Puerto Naos and three permanent CO2 monitoring stations. Diffuse CO2 efflux values measured in the Puerto Naos area were relatively low (between not detected and 24 g m-2 d-1). However, in numerous points of the built-up area of Puerto Naos, air CO2 concentration values measured both in the street at a height of about 40 cm and in the lower part of several garage doors were generally over 1-2%V, with some sites with values higher than 20%V. The area with the highest CO2 diffuse efflux values is located in the La Bombilla neighborhood, reaching values higher than 7 kg m-2 d-1. δ13C-CO2 values of soil gases ranged from -19.2 to -1.7‰ vs. VPDB, confirming a volcanic-hydrothermal origin for those samples exhibiting high CO2 effluxes and concentration. No H2S effluxes as well as air concentrations were registered. During the survey, many animals were found dead due to high concentrations of CO2 and low levels of O2 in the air .All these anomalous CO2 emissions are not associated to thermal anomalies. Results of this study show that in many sites at La Bombilla and Puerto Naos areas there is a dangerous CO2 air concentration that exceeds the hazardous thresholds. These zones should be continuously monitored for gas hazard and the multi-measurement approach adopted in the present study is of paramount importance for decision-making of people's return to their homes.

How to cite: Hernández, P. A., Padrón, E., Melián, G. V., Pérez, N. M., Padilla, G., Asensio-Ramos, M., Di Nardo, D., Barrancos, J., Pacheco, J. M., and Smit, M.: Gas hazard assessment at Puerto Naos and La Bombilla inhabited areas, Cumbre Vieja volcano, La Palma, Canary Islands, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7705, https://doi.org/10.5194/egusphere-egu22-7705, 2022.

15:40–15:46
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EGU22-3253
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Virtual presentation
Fátima Viveiros, Diogo Henriques, José Pacheco, Alexandra Moutinho, Marcos Martins, Sérgio Oliveira, Dário Silva, Tiago Matos, Pedro Hernández, Nemesio Pèrez, Catarina Goulart, Diamantino Henriques, Paulo Fialho, Luís Gonçalves, Carlos Faria, João Rocha, Eleazar Padrón, Jose Barrancos, and María Asensio-Ramos

Volcanic gases and particulate matter (PM) can be hazardous for population not only during an eruptive event, but also during the post-eruption phase, even at significant distances from the volcanic edifice. Volcanic plume dispersion can be affected by diverse factors, such as the weather conditions (e.g., wind speed and direction, rainfall) and/or the topography. Several studies have showed that gas concentrations and PM impacts on the quotidian life during a volcanic crisis can be significant, highlighting the importance of setting up permanent monitoring systems.

Instruments with carbon dioxide (CO2), sulphur dioxide (SO2)and particulate matter (PM2.5 and PM10) low-cost sensors were developed in order to easily and continuously monitor any volcanic area, and the 2021 Cumbre Vieja eruption was chosen as test site to deploy and validate the instrumentation. A network of nine instruments was set up around the volcanic eruption site, covering both the north and south areas of the lava flows, at distances varying between 1.6 and 7 km from the volcano craters. Five instruments were designed to work autonomously in the field, powered by batteries, and the electrical network powered the other four sensors. All nine instruments broadcasted the recorded data via LoRa communication.

The network settled after the 9th December 2021, closer to the ending of the eruptive period, recorded maximum CO2 concentrations of 1585 ppm at station named “Perm-2”, located at about 4.8 km distance from the volcanic craters, on the 21st December 2021. Regarding particulate matter, even if the 24 hour-mean standards set by the World Health Organization (WHO) for the PM2.5 and PM10 (25 mg/m3 and 50 mg/m3, respectively) were not exceeded during the monitored period, maximum concentrations were also recorded for these two parameters (470 and 874 mg/m3) at “Perm-2” in the 21st December. For the same period, the station located closer to the volcano craters measured maximum SO2 concentrations of 1.11 ppm. Maximum PM values were recorded also at other two monitoring sites in the same day, suggesting spatial and temporal correlation between the different parameters. In this particular case, and considering that maximum concentrations were registered during the night in the exclusion zone, one can reject the potential association of the measured values with suspended ashes resulting from sweeping and cleaning activities. For other periods, particularly after the ending of the eruption, this association must be considered. The highest concentrations of particles post-eruption were measured in the 31st December 2021 and 3rd January 2022.

The installed instruments seem to be adequate for an easier and faster deploy during a volcanic crises, allowing recognizing the presence of hazardous gas and particulate matter concentrations, crucial to reduce potential health effects on the population, even after the end of the eruptive phase.

How to cite: Viveiros, F., Henriques, D., Pacheco, J., Moutinho, A., Martins, M., Oliveira, S., Silva, D., Matos, T., Hernández, P., Pèrez, N., Goulart, C., Henriques, D., Fialho, P., Gonçalves, L., Faria, C., Rocha, J., Padrón, E., Barrancos, J., and Asensio-Ramos, M.: Air quality real-time monitoring during volcanic crises with low-cost sensors: the Cumbre Vieja volcano study case, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3253, https://doi.org/10.5194/egusphere-egu22-3253, 2022.

Communication and Risk
15:46–15:52
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EGU22-7722
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Highlight
David Calvo, María Asensio-Ramos, Pedro A. Hernández, Luca D’Auria, Matthew J. Pankhurst, Nemesio M. Pérez, Fátima Rodríguez, Eleazar Padrón, Germán D. Padilla, José Barrancos, Berverly C. Coldwell, and VIctoria Leal

The 2021 Cumbre Vieja eruption has provided powerful insights not only on the pure research field, but as well on the communication side. From INVOLCAN we´ve developed a clear strategy on how to communicate what was going on, and about the role of science on this eruption. But there is as well a long road to let the different audiences understand the ultimate goal of an institutional profile, that is telling about science and nothing else related to the drama lived by the population. That strategy led us to show anything but science, discarding tons of footage of destruction of infrastructure and properties.

Through the eruption our Twitter and Facebook profiles published the same content, with a clear divergence on the output. While Facebook followers remained almost stagnant all over the 3 months period, the Twitter account skyrocketed to a +-5000% increase on followers, and almost 100M tweet impressions. We focused on working on a single profile rather than in personal profiles of researchers, where part of the message and the influence can be lost in time

All our graphic material was released as public domain, what resulted in hundreds of INVOLCAN TV hours, and led to hundreds of interviews on media from anywhere in the world. The impact of the INVOLCAN brand is literally unaccountable and we believe strengthens the Institute reputation all over.

But we have discovered some flaws as well on the “relationship” established between the “speaker” (INVOLCAN) and the “audience”. As massive attention was driven to the INVOLCAN account, the number of trolls and eccentric characters emerged. This is a well-known behaviour on social media, but never happened before to us on that scale.

A clear ignorance of the objectives of INVOLCAN may explain part of some feedback received, which perhaps did not understand well that INVOLCAN was not responsible for emergency tasks such as evacuations, or that it was not responsible for showing the destruction of private property or that at least it wasn't our job.

But there is still an important part of the work to be done, insofar as it is exhausting to see the proliferation of "experts" capable of demanding information that does not make any sense to the population or that directly accused of hiding information.

There is a long way to go in the world of social networks, and this eruption, the same as that of the COIVD-19 pandemic, has revealed the multiple menaces that threaten science lurking in the shadows, which may end up losing its voice in a tower of Babylon where anyone thinks they know the language of volcanoes

How to cite: Calvo, D., Asensio-Ramos, M., Hernández, P. A., D’Auria, L., Pankhurst, M. J., Pérez, N. M., Rodríguez, F., Padrón, E., Padilla, G. D., Barrancos, J., Coldwell, B. C., and Leal, V.: @Involcan communication strategies on the 2021 Cumbre Vieja eruption: Of do´s, don´ts, trolls and other fantastic beasts, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7722, https://doi.org/10.5194/egusphere-egu22-7722, 2022.

15:52–15:58
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EGU22-12678
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ECS
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Highlight
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Virtual presentation
Lucia Dominguez Barragan, Luigia Di Maio, Maria-Paz Reyes Hardy, Corine Frischknecht, Giulio Zuccaro, Nemesio Perez, and Costanza Bonadonna

Long-lasting volcanic eruptions involving a variety of hazards have significant implications on the emergency response and on the final impact on the exposed elements. The eruption of Cumbre Vieja (La Palma, Spain), started on 19 September and ended on 13 December 2021. It was associated with earthquakes, gas emissions, lava flows, lava fountains, and tephra fallout (including large volcanic bombs) that significantly impacted the southwest of the island, caused the evacuation of more than 7,000 people and affected 1,676 buildings. In particular, the total extension of about 12 km2 of lava flows, from the fissural source to the western coast, affected 3 municipalities and cut the island in two, generating a significant disruption of transportation. A comprehensive and systematic survey of about 300 buildings affected by tephra south of the lava flow was carried out during two weeks in October 2021 in order to assess the typology of affected buildings and the associated structural and non-structural damages. Structural damage was associated with partial or total roof collapse of secondary buildings (small independent constructions for warehouse, farming and garage) and annexes (small dependent constructions annexed to the main buildings). The most common non-structural damages include clamping vertical and horizontal cracks, partial or total overturning of walls (in case of clamping or thrust of the stressed roofs), and partial damage of several elements (tiles, plaster, curbs, canopies, parapets, windows, corrugate and fretted sheets and tarps). No major structural damage was observed on main buildings. The reason is due to the fact that primary residential and commercial buildings were considered necessary to meet basic needs of the local population; therefore, roofs were regularly cleaned as part of the emergency management and the daily volcanic response activity on the island. This was not the case for secondary buildings and annexes. This emphasizes the important role of clean-up operations on the resilience of buildings during long-lasting volcanic eruptions that can lapse for weeks or months. Even though structural damage has been observed only on secondary structures and annexes, the detailed impact assessment of those conducted in La Palma provides the first insights into the consequences of tephra loads on medium to weak quality buildings or constructions made with light materials (e.g., corrugated metallic tiles), which can be very common on other volcanic settings.

How to cite: Dominguez Barragan, L., Di Maio, L., Reyes Hardy, M.-P., Frischknecht, C., Zuccaro, G., Perez, N., and Bonadonna, C.: Impact assessment of buildings exposed to the tephra fallout of the 2021 Cumbre Vieja eruption in La Palma, Spain , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12678, https://doi.org/10.5194/egusphere-egu22-12678, 2022.

15:58–16:04
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EGU22-12449
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Virtual presentation
Antonio Eff-Darwich, Pablo J. González, Begoña García-Lorenzo, Julio Castro-Almazán, Juan Carlos Pérez-Arencibia, and Jose Antonio Rodríguez-Losada

In 2010, it was published an analysis of the impact of geological activity on the main astronomical observatories worldwide (Eff-Darwich et al., 2010), among them, Roque de los Muchachos observatory (ORM), in the island of La Palma, Canary Islands (Spain). In this work, we compare the results on geological risk at ORM that were obtained in 2010 with the actual impact  of Cumbre Vieja eruption. In this sense, we studied the effects of seismicity, ash fall, landslides and ground deformation at ORM. In general, we found a good agreement between the expected and actual impact of volcanic activity at the observatory; however, large differences were found in the distribution of ash fall, likely due to the improper characterization of the atmospheric inversion layer in the model of the dispersion of the volcanic plume.

 

Eff-Darwich, A., García-Lorenzo, B., Rodríguez-Losada, J., de la Nuez, J., Hernández-Gutiérrez, L., Romero, C., Monthly Notices of the Royal Astronomical Society, Volume 407, Issue 3, September 2010, Pages 1361–1375, https://doi.org/10.1111/j.1365-2966.2010.16925.x

How to cite: Eff-Darwich, A., González, P. J., García-Lorenzo, B., Castro-Almazán, J., Pérez-Arencibia, J. C., and Rodríguez-Losada, J. A.: Geological risk at Roque de los Muchachos astronomical observatory: lessons learned from Cumbre Vieja eruption. , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12449, https://doi.org/10.5194/egusphere-egu22-12449, 2022.

16:04–16:10
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EGU22-12852
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Highlight
Juan Carlos Pérez-Arencibia, Julio A. Castro-Almazán, Antonio Eff-Darwich, David García-Álvarez, Jon Vilches-Sarasate, Víctor Gallo-Acosta, Begoña García-Lorenzo, and Casiana Muñoz-Tuñón

Between September 19 and December 13, 2021 a strombolian volcanic eruption took place on the island of La Palma. The main edifice was appeared at an altitude of around 900 masl, reaching 1122 masl at the end of the process. The Roque de los Muchachos Observatory (ORM) is an outstanding international astronomical site, hosting some of the most important astrophysical facilities of the world. The Observatory is located 16 km away from the eruptive cone, in the summit of the island, at an altitude ranging between 2200 and 2400 masl. The atmospheric conditions at the Canary Islands conform an almost permanent thermal inversion layer below the level of the observatory that modulated the arrival of the volcanic plume. In this work we are going to briefly review the influence of different parameters associated to the eruption in the ORM routine operation. We will evaluate the impact of the seismic activity, volcanic ash falling, presence of SO2 and airborne particulate matter. The number of days with high remarkable values recorded of these parameters were few. Nevertheless, the actual impact on the different telescopes was heterogeneous, depending on the different risk evaluations, and recovery/response times. An impact report with a compilation of measurements and forecasts was released twice a day during the whole process to help facilities in the daily operational decision making. As a final conclusion, no damages were suffered in any of the installations. Although an important downtime was reported, astronomical observations continued in different degree during the whole episode.

 

How to cite: Pérez-Arencibia, J. C., Castro-Almazán, J. A., Eff-Darwich, A., García-Álvarez, D., Vilches-Sarasate, J., Gallo-Acosta, V., García-Lorenzo, B., and Muñoz-Tuñón, C.: Impact at the astronomical Observatory of Roque de los Muchachos from the Cumbre Vieja 2021 volcanic eruption at La Palma., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12852, https://doi.org/10.5194/egusphere-egu22-12852, 2022.